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Sample records for 2d6-mediated dextromethorphan o-demethylation

  1. Inhibition of CYP2D6-mediated tramadol O-demethylation in methadone but not buprenorphine maintenance patients

    PubMed Central

    Coller, Janet K; Michalakas, Jennifer R; James, Heather M; Farquharson, Aaron L; Colvill, Joel; White, Jason M; Somogyi, Andrew A

    2012-01-01

    AIMS To compare the O- (CYP2D6 mediated) and N- (CYP3A4 mediated) demethylation metabolism of tramadol between methadone and buprenorphine maintained CYP2D6 extensive metabolizer subjects. METHODS Nine methadone and seven buprenorphine maintained subjects received a single 100 mg dose of tramadol hydrochloride. Blood was collected at 4 h and assayed for tramadol, methadone, buprenorphine and norbuprenorphine (where appropriate) and all urine over 4 h was assayed for tramadol and its M1 and M2 metabolites. RESULTS The urinary metabolic ratio [median (range)] for O-demethylation (M1) was significantly lower (P= 0.0002, probability score 1.0) in the subjects taking methadone [0.071 (0.012–0.103)] compared with those taking buprenorphine [0.192 (0.108–0.392)], but there was no significant difference (P= 0.21, probability score 0.69) in N-demethylation (M2). The percentage of dose [median (range)] recovered as M1 was significantly lower in subjects taking methadone compared with buprenorphine (0.069 (0.044–0.093) and 0.126 (0.069–0.187), respectively, P= 0.04, probability score 0.19), M2 was significantly higher in subjects taking methadone compared with buprenorphine (0.048 (0.033–0.085) and 0.033 (0.014–0.049), respectively, P= 0.04, probability score 0.81). Tramadol was similar (0.901 (0.635–1.30) and 0.685 (0.347–1.04), respectively, P= 0.35, probability score 0.65). CONCLUSIONS Methadone inhibited the CYP2D6-mediated metabolism of tramadol to M1. Hence, as the degree of opioid analgesia is largely dependent on M1 formation, methadone maintenance patients may not receive adequate analgesia from oral tramadol. PMID:22369095

  2. Frequencies of CYP2D6 mutant alleles in a normal Japanese population and metabolic activity of dextromethorphan O-demethylation in different CYP2D6 genotypes

    PubMed Central

    Kubota, T; Yamaura, Y; Ohkawa, N; Hara, H; Chiba, K

    2000-01-01

    Aims To determine the frequencies of 11 CYP2D6 mutant alleles (CYP2D6*2,*3,*4,*5,*8,*10,*11,*12,*14,*17 and *18), and their relation to the metabolic capacity of CYP2D6 in Japanese subjects. Methods One hundred and sixty-two unrelated healthy Japanese subjects were genotyped with the polymerase chain reaction amplification method and 35 subjects were phenotyped with dextromethorphan. Results The frequencies of CYP2D6*2,*5, *10 and *14 were 12.9, 6.2, 38.6 and 2.2% in our Japanese subjects, respectively. CYP2D6*3, *4, *8, *11, *12, *17 and *18 were not detected. The mean log metabolic ratio of dextromethorphan in subjects with genotypes predicting intermediate metabolizers was significantly greater than that of heterozygotes for functional and defective alleles. Conclusions CYP2D6*5 and CYP2D6*14 are the major defective alleles found in Japanese subjects. In addition, CYP2D6*10 may play a more important role than previously thought for the treatment of Japanese patients with drugs metabolized by CYP2D6. PMID:10886115

  3. Dextromethorphan

    MedlinePlus

    Children's Robitussin Cough Long-Acting® ... Vicks DayQuil Cough® ... Vicks Formula 44 Custom Care Dry Cough® ... Zicam Cough MAX® ... Dextromethorphan is used to temporarily relieve cough caused by the common cold, the flu, or other conditions. Dextromethorphan will relieve a cough but will not treat the cause of ...

  4. Effect of black seed on dextromethorphan O- and N-demethylation in human liver microsomes and healthy human subjects.

    PubMed

    Al-Jenoobi, F I; Al-Thukair, A A; Abbas, F A; Ansari, M J; Alkharfy, K M; Al-Mohizea, A M; Al-Suwayeh, S A; Jamil, S

    2010-01-01

    To investigate the effects of black seed on the metabolic activities of CYP3A4 and CYP2D6 in human liver microsomes and in human subjects using dextromethorphan as a probe drug. CYP2D6-mediated O-demethylation and CYP3A4-mediated N-demethylation of dextromethorphan (DEX) to dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively, were utilized to assess the metabolic activities of the two enzymatic pathways. In the in vitro experiments, DEX was incubated with microsomes and NADPH in absence or presence of black seed extract (10-100 microg/ml) and the formation of the metabolites were measured by HPLC. In the clinical study, four healthy volunteers received a single oral dose of DEX 30 mg alone in phase I, and along with last dose of black seed (2.5 g twice daily for seven days) in phase II. Activities of the two enzymes were evaluated based on the urinary metabolic ratios (MRs), which were calculated from eight-hour urine collections. DEX and its metabolites were assayed in urine samples by HPLC following a liquid-liquid extraction. Black seed extracts significantly inhibited the formation of both metabolites in microsomes. The maximum inhibition was observed at the highest extract concentration (i.e., 100 microg/ml), which was about 80% and 60% for DOR and 3-MM, respectively. In the clinical study, the urinary MRs of DEX/DOR and DEX/3-MM increased by factors of 127 and 1.6-fold, respectively, after consumption of black seed. Black seed significantly inhibited CYP2D6 and CYP3A4 mediated metabolism of DEX in human liver microsomes and healthy human volunteers indicating that it has the potential to interact with CYP2D6 and CYP3A4 substrates.

  5. Anaerobic O-demethylation of phenylmethylethers

    SciTech Connect

    Frazer, A.C.; Young, L.Y.

    1990-01-01

    Anaerobic O-demethylation (AOD) of phenylmethylethers is a process of both basic and applied significance. The aryl-O-methyl ethers are abundant in natural products, particularly as components of lignin. They are present as methoxylated lignin monomers in anaerobic environments and can be completely degraded there by mixed microbial populations. AOD is an essential early step in this process, and it is also a key reaction in the utilization of the O-methyl substituent as a C-one substrate by acetogens. An understanding of the AOD reaction mechanism might suggest new ways in which chemicals could be derived from lignocellulosic materials. The biochemical mechanism for the anaerobic cleavage of the aryl-O-methyl ether bond is an intriguing, but relatively unexplored process. In contrast to aerobic O-demethylating enzymes, AOD appears to involve methyl group transfer. Thus, novel biochemical information on an important biotransformation reaction will be gained from the research proposed. Recently, we have shown that AOD activity is inducible and have developed an assay for detecting AOD activity in cell-free extracts of Acetobacterium woodii. AOD activity is stimulated in vitro by the addition of ATP (1mM) and pyruvate (30 mM), the K{sub M} for vanillate being 0.4 mM. In collaboration with protein purification experts, we proposed to purify the AOD enzyme and characterize the protein(s) and the enzymatic reaction involved. 8 figs., 5 tabs.

  6. Inhibition of cytochrome P450 by nefazodone in vitro: studies of dextromethorphan O- and N-demethylation

    PubMed Central

    SCHMIDER, JÜRGEN; GREENBLATT, DAVID J.; VON MOLTKE, LISA L.; HARMATZ, JEROLD S.; SHADER, RICHARD I.

    1996-01-01

    Nefazodone (NEF), a 5-HT2A/2C antagonist antidepressant, is extensively metabolized in the human body to hydroxy NEF (OH-NEF), p-hydroxy NEF (pOH-NEF), a dione metabolite, and via cleavage of the molecule to m-chlorophenyl-piperazine (mCPP) and BMY-33604. The latter is further metabolized to BMS-183695-01 (BMSa) and BMS-183562-01 (BMSb). To investigate the potential of NEF and its metabolites to interfere with the metabolism of other drugs, we tested these compounds for their ability to alter dextromethorphan (DMO) O-demethylation to dextrorphan (DOP; an index reaction for CYP2D6) and N-demethylation to 3-methoxy morphinan (MEM, a recently proposed index reaction of CYP3A3/4). The assay was performed in an in vitro system with human liver microsomes from three different donors. NEF, OH-NEF, pOH-NEF, mCPP and BMSb were weak inhibitors of DMO O and N-demethylation, with average Ki values ranging from 18 to 50 μm for DOP formation, and from 21 to >200 μm for MEM formation. The dione metabolite and BMSa did not produce detectable inhibition of either pathway. The findings for DMO O-demethylation, well-established as a CYP2D6-mediated reaction, indicate that NEF and metabolites are weak inhibitors of this reaction, with Ki values at least 100 times higher than fluoxetine (Ki=0.1 μm±0.09). The implications of results on DMO N-demethylation are not clear. In vivo data, as well as in vitro data based on ‘pure’ CYP3A3/4 substrates, provide evidence for clinically relevant CYP3A3/4 inhibition by NEF, OH-NEF, and pOH-NEF. Thus, formation of MEM by N-demethylation of DMO may not constitute a suitable index reaction to probe CYP3A3/4 activity. PMID:8730981

  7. Synthesis of Hydroxytripelennamine via O-Demethylation of Pyrilamine

    DTIC Science & Technology

    1988-06-01

    connecting methylene groups was dramatically shifted down field, suggesting that changes in the electronic environment of the molecule had occurred. The...the nucleophile. This reaction has been previously used to convert codeine to morphine. 11 The reaction of Compound 3 with 1-propanethiol and potassium...Degraw, J.I.,"An Improved Method for O-Demethylation of Codeine ," J. Med. Chem. Vol. 20, p 165 (19b77). 13 "".* , H I f ~ I * J IJ I ~ E A’ 12. Ho, T-L

  8. Biochemistry and Occurrence of O-Demethylation in Plant Metabolism

    PubMed Central

    Hagel, Jillian M.; Facchini, Peter J.

    2010-01-01

    Demethylases play a pivitol role in numerous biological processes from covalent histone modification and DNA repair to specialized metabolism in plants and microorganisms. Enzymes that catalyze O- and N-demethylation include 2-oxoglutarate (2OG)/Fe(II)-dependent dioxygenases, cytochromes P450, Rieske-domain proteins and flavin adenine dinucleotide (FAD)-dependent oxidases. Proposed mechanisms for demethylation by 2OG/Fe(II)-dependent enzymes involve hydroxylation at the O- or N-linked methyl group followed by formaldehyde elimination. Members of this enzyme family catalyze a wide variety of reactions in diverse plant metabolic pathways. Recently, we showed that 2OG/Fe(II)-dependent dioxygenases catalyze the unique O-demethylation steps of morphine biosynthesis in opium poppy, which provides a rational basis for the widespread occurrence of demethylases in benzylisoquinoline alkaloid metabolism. PMID:21423357

  9. Understanding the determinants of selectivity in drug metabolism through modeling of dextromethorphan oxidation by cytochrome P450.

    PubMed

    Oláh, Julianna; Mulholland, Adrian J; Harvey, Jeremy N

    2011-04-12

    Cytochrome P450 enzymes play key roles in the metabolism of the majority of drugs. Improved models for prediction of likely metabolites will contribute to drug development. In this work, two possible metabolic routes (aromatic carbon oxidation and O-demethylation) of dextromethorphan are compared using molecular dynamics (MD) simulations and density functional theory (DFT). The DFT results on a small active site model suggest that both reactions might occur competitively. Docking and MD studies of dextromethorphan in the active site of P450 2D6 show that the dextromethorphan is located close to heme oxygen in a geometry apparently consistent with competitive metabolism. In contrast, calculations of the reaction path in a large protein model [using a hybrid quantum mechanical-molecular mechanics (QM/MM) method] show a very strong preference for O-demethylation, in accordance with experimental results. The aromatic carbon oxidation reaction is predicted to have a high activation energy, due to the active site preventing formation of a favorable transition-state structure. Hence, the QM/MM calculations demonstrate a crucial role of many active site residues in determining reactivity of dextromethorphan in P450 2D6. Beyond substrate binding orientation and reactivity of Compound I, successful metabolite predictions must take into account the detailed mechanism of oxidation in the protein. These results demonstrate the potential of QM/MM methods to investigate specificity in drug metabolism.

  10. Understanding the determinants of selectivity in drug metabolism through modeling of dextromethorphan oxidation by cytochrome P450

    PubMed Central

    Oláh, Julianna; Mulholland, Adrian J.; Harvey, Jeremy N.

    2011-01-01

    Cytochrome P450 enzymes play key roles in the metabolism of the majority of drugs. Improved models for prediction of likely metabolites will contribute to drug development. In this work, two possible metabolic routes (aromatic carbon oxidation and O-demethylation) of dextromethorphan are compared using molecular dynamics (MD) simulations and density functional theory (DFT). The DFT results on a small active site model suggest that both reactions might occur competitively. Docking and MD studies of dextromethorphan in the active site of P450 2D6 show that the dextromethorphan is located close to heme oxygen in a geometry apparently consistent with competitive metabolism. In contrast, calculations of the reaction path in a large protein model [using a hybrid quantum mechanical–molecular mechanics (QM/MM) method] show a very strong preference for O-demethylation, in accordance with experimental results. The aromatic carbon oxidation reaction is predicted to have a high activation energy, due to the active site preventing formation of a favorable transition-state structure. Hence, the QM/MM calculations demonstrate a crucial role of many active site residues in determining reactivity of dextromethorphan in P450 2D6. Beyond substrate binding orientation and reactivity of Compound I, successful metabolite predictions must take into account the detailed mechanism of oxidation in the protein. These results demonstrate the potential of QM/MM methods to investigate specificity in drug metabolism. PMID:21444768

  11. Dextromethorphan Abuse in Adolescence

    PubMed Central

    Bryner, Jodi K.; Wang, Uerica K.; Hui, Jenny W.; Bedodo, Merilin; MacDougall, Conan; Anderson, Ilene B.

    2008-01-01

    Objectives To analyze the trend of dextromethorphan abuse in California and to compare these findings with national trends. Design A 6-year retrospective review. Setting California Poison Control System (CPCS), American Association of Poison Control Centers (AAPCC), and Drug Abuse Warning Network (DAWN) databases from January 1, 1999, to December 31, 2004. Participants All dextromethorphan abuse cases reported to the CPCS, AAPCC, and DAWN. The main exposures of dextromethorphan abuse cases included date of exposure, age, acute vs long-term use, coingestants, product formulation, and clinical outcome. Main Outcome Measure The annual proportion of dextromethorphan abuse cases among all exposures reported to the CPCS, AAPCC, and DAWN databases. Results A total of 1382 CPCS cases were included in the study. A 10-fold increase in CPCS dextromethorphan abuse cases from 1999 (0.23 cases per 1000 calls) to 2004 (2.15 cases per 1000 calls) (odds ratio, 1.48; 95% confidence interval, 1.43–1.54) was identified. Of all CPCS dextromethorphan abuse cases, 74.5% were aged 9 to 17 years; the frequency of cases among this age group increased more than 15-fold during the study (from 0.11 to 1.68 cases per 1000 calls). Similar trends were seen in the AAPCC and DAWN databases. The highest frequency of dextromethorphan abuse occurred among adolescents aged 15 and 16 years. The most commonly abused product was Coricidin HBP Cough & Cold Tablets. Conclusions Our study revealed an increasing trend of dextromethorphan abuse cases reported to the CPCS that is paralleled nationally as reported to the AAPCC and DAWN. This increase was most evident in the adolescent population. PMID:17146018

  12. Chiral analyses of dextromethorphan/levomethorphan and their metabolites in rat and human samples using LC-MS/MS.

    PubMed

    Kikura-Hanajiri, Ruri; Kawamura, Maiko; Miyajima, Atsuko; Sunouchi, Momoko; Goda, Yukihiro

    2011-04-01

    In order to develop an analytical method for the discrimination of dextromethorphan (an antitussive medicine) from its enantiomer, levomethorphan (a narcotic) in biological samples, chiral analyses of these drugs and their O-demethyl and/or N-demethyl metabolites in rat plasma, urine, and hair were carried out using LC-MS/MS. After the i.p. administration of dextromethorphan or levomethorphan to pigmented hairy male DA rats (5 mg/kg/day, 10 days), the parent compounds and their three metabolites in plasma, urine and hair were determined using LC-MS/MS. Complete chiral separation was achieved in 12 min on a Chiral CD-Ph column in 0.1% formic acid-acetonitrile by a linear gradient program. Most of the metabolites were detected as being the corresponding O-demethyl and N, O-didemethyl metabolites in the rat plasma and urine after the hydrolysis of O-glucuronides, although obvious differences in the amounts of these metabolites were found between the dextro and levo forms. No racemation was observed through O- and/or N-demethylation. In the rat hair samples collected 4 weeks after the first administration, those differences were more clearly detected and the concentrations of the parent compounds, their O-demethyl, N-demethyl, and N, O-didemethyl metabolites were 63.4, 2.7, 25.1, and 0.7 ng/mg for the dextro forms and 24.5, 24.6, 2.6, and 0.5 ng/mg for the levo forms, respectively. In order to fully investigate the differences of their metabolic properties between dextromethorphan and levomethorphan, DA rat and human liver microsomes were studied. The results suggested that there might be an enantioselective metabolism of levomethorphan, especially with regard to the O-demethylation, not only in DA rat but human liver microsomes as well. The proposed chiral analyses might be applied to human samples and could be useful for discriminating dextromethorphan use from levomethorphan use in the field of forensic toxicology, although further studies should be carried out

  13. Importance of tetrahydrofolate and ATP in the anaerobic O-demethylation reaction for phenylmethylethers

    SciTech Connect

    Berman, M.H.; Frazer, A.C. )

    1992-03-01

    DL-Tetrahydrofolate (THF) and ATP were necessary for the anaerobic O-demethylation of phenylmethylethers in cell extracts of the type strain (ATCC 29683) of the homoacetogen Acetobacterium woodii. The reactants for this enzymatic activity have not been previously demonstrated in any system, nor has the mediating enzyme been studied. An assay using reaction mixtures containing 1 mM THF, 2 mM ATP, and 2 mM hydroferulate (i.e., 4-hydroxy,3-methoxyphenylpropionate) was developed and was performed under stringent anaerobic conditions. Pyridine nucleotides and several other possible cofactors were tested but had no effect on the activity. After centrifugation of disrupted cells at 27,000 x g, the activity was found primarily in the supernatant, which had a specific activity of 14.2 {plus minus} 0.5 nmol/min/mg of protein. At saturating levels of each of the other two substrates, apparent K{sub m} values for the variable substrate were 0.65 mM hydroferulate, 0.27 mM ATP, and 0.17 mM THF. Activity was significantly decreased when extract was preincubated at 60C and was completely lost after preincubation in air for 30 min. Thus, the soluble anaerobic O-demethylating enzyme system of A. woodii is oxygen sensitive. The THF- and ATP-dependent activity measurable in the soluble fraction of cell extracts constituted about 34% of the activity seen with intact cells.

  14. Inhalant Abuse and Dextromethorphan.

    PubMed

    Storck, Michael; Black, Laura; Liddell, Morgan

    2016-07-01

    Inhalant abuse is the intentional inhalation of a volatile substance for the purpose of achieving an altered mental state. As an important, yet underrecognized form of substance abuse, inhalant abuse crosses all demographic, ethnic, and socioeconomic boundaries, causing significant morbidity and mortality in school-aged and older children. This review presents current perspectives on epidemiology, detection, and clinical challenges of inhalant abuse and offers advice regarding the medical and mental health providers' roles in the prevention and management of this substance abuse problem. Also discussed is the misuse of a specific "over-the-counter" dissociative, dextromethorphan.

  15. Dextromethorphan withdrawal and dependence syndrome.

    PubMed

    Mutschler, Jochen; Koopmann, Anne; Grosshans, Martin; Hermann, Derik; Mann, Karl; Kiefer, Falk

    2010-07-01

    The N-methyl-D-aspartate (NMDA) antagonist dextromethorphan has been available in pharmacies without a prescription since 1954 as an antitussive agent. There is an alarming increase in reports of its abuse. Dextromethorphan is avidly taken, mainly by young people, as a psychoactive drug. The currently available data yield incomplete information about the extent of the problem and its significance for addiction medicine in Germany. We report the case of a 44-year-old man who became dependent on dextromethorphan through years of abuse, buying the substance for himself without a prescription in German pharmacies. He told us he had taken it regularly for six years. He had become dependent on dextromethorphan, ultimately taking it in a dose of 1800 mg daily. This led him to overt neglect of his work and leisure activities. A urine sample taken on admission to the hospital was found to contain dextromethorphan. During inpatient detoxification, he developed an vegetative withdrawal syndrome consisting of craving, diaphoresis, nausea, hypertension, and tachycardia. He was treated on our ward for three weeks, and a stay in a residential detoxification facility was planned thereafter. Dextromethorphan is a psychotropic substance that carries a potential for abuse and dependence. On the basis of the currently available data, its reclassification as a prescription drug should be considered.

  16. Anaerobic O-demethylations of methoxynaphthols, methoxyfuran, and fluoroanisols by Sporomusa ovata.

    PubMed

    Stupperich, E; Konle, R; Eckerskorn, C

    1996-06-25

    In vitro experiments with 3,4-dimethoxybenzoate-induced Sporomusa enzymes a broad O-methyl ether cleavage capacity. The O-demethylase activity hydrolized the methyl-oxygen linkages of methoxynaphtholes of the heterocycles 2-methoxyfuran or 2-methoxythiophene as well as of several dimethoxy and monomethoxy aryls under anaerobic conditions. Also, fluoro and chloro substituents of anisoles enhanced the O-demethylation rate, indicating that an electron delocalized aromatic structure supported the methyl ether activation mechanism. Monomethoxy aromatics with additional chargeable groups, however, were less effectively transformed by the O-demethylase activity. No transformations into hydroxylated products occurred with 4-(trifluoromethoxy)benzyl alcohol, 4-(trifluoromethoxy)fluorobenzene, 2,5-dimethoxytetrahydrofuran, or alkyl-O-methyl ethers. The inert ethers did not affect the 3,4-dimethoxybenzoate metabolism. Ether activation or the following methyl transfer to the methyl acceptor tetrahydrofolate involved a prominent 31 kDa peptide from the cytoplasmic cell fraction, because this particular peptide was lacking in cells grown with methanol, betaine or fructose.

  17. O-Demethylation and Successive Oxidative Dechlorination of Methoxychlor by Bradyrhizobium sp. Strain 17-4, Isolated from River Sediment

    PubMed Central

    Masuda, Minoru; Sato, Kiyoshi

    2012-01-01

    O-Demethylation of insecticide methoxychlor is well known as a phase I metabolic reaction in various eukaryotic organisms. Regarding prokaryotic organisms, however, no individual species involved in such reaction have been specified and characterized so far. Here we successfully isolated a bacterium that mediates oxidative transformation of methoxychlor, including O-demethylation and dechlorination, from river sediment. The isolate was found to be closely related to Bradyrhizobium elkanii at the 16S rRNA gene sequence level (100% identical). However, based on some differences in the physiological properties of this bacterium, we determined that it was actually a different species, Bradyrhizobium sp. strain 17-4. The isolate mediated O-demethylation of methoxychlor to yield a monophenolic derivative [Mono-OH; 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane] as the primary degradation product. The chiral high-performance liquid chromatography (HPLC) analysis revealed that the isolate possesses high enantioselectivity favoring the formation of (S)-Mono-OH (nearly 100%). Accompanied by the sequential O-demethylation to form the bis-phenolic derivative Bis-OH [1,1,1-trichloro-2,2-bis(4-hydroxyphenyl)ethane], oxidative dechlorination of the side chain proceeded, and monophenolic carboxylic acid accumulated, followed by the formation of multiple unidentified polar degradation products. The breakdown proceeded more rapidly when reductively dechlorinated (dichloro-form) methoxychlor was applied as the initial substrate. The resultant carboxylic acids and polar degradation products are likely further biodegraded by ubiquitous bacteria. The isolate possibly plays an important role for complete degradation (mineralization) of methoxychlor by providing the readily biodegradable substrates. PMID:22635993

  18. An effective O-demethylation of some C19-diterpenoid alkaloids with HBr-glacial acetic acid.

    PubMed

    Zou, Chun-Lan; Ji, Hong; Xie, Guang-Bo; Chen, Dong-Lin; Wang, Feng-Peng

    2008-01-01

    The aconitine-type alkaloids talatisamine (1), 8,14-diacetyltalatisamine (11), and compound 3, the lycoctonine-type alkaloid deltaline (5), and the 7,17-seco C(19)-diterpenoid alkaloids 7 and 9 were treated with HBr-glacial acetic acid to give useful O-demethylated derivatives 2, 2, 4, 6, 8, and 10 respectively in good to high yields (49-90%).

  19. O-Demethylation and successive oxidative dechlorination of methoxychlor by Bradyrhizobium sp. strain 17-4, isolated from river sediment.

    PubMed

    Satsuma, Koji; Masuda, Minoru; Sato, Kiyoshi

    2012-08-01

    O-Demethylation of insecticide methoxychlor is well known as a phase I metabolic reaction in various eukaryotic organisms. Regarding prokaryotic organisms, however, no individual species involved in such reaction have been specified and characterized so far. Here we successfully isolated a bacterium that mediates oxidative transformation of methoxychlor, including O-demethylation and dechlorination, from river sediment. The isolate was found to be closely related to Bradyrhizobium elkanii at the 16S rRNA gene sequence level (100% identical). However, based on some differences in the physiological properties of this bacterium, we determined that it was actually a different species, Bradyrhizobium sp. strain 17-4. The isolate mediated O-demethylation of methoxychlor to yield a monophenolic derivative [Mono-OH; 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane] as the primary degradation product. The chiral high-performance liquid chromatography (HPLC) analysis revealed that the isolate possesses high enantioselectivity favoring the formation of (S)-Mono-OH (nearly 100%). Accompanied by the sequential O-demethylation to form the bis-phenolic derivative Bis-OH [1,1,1-trichloro-2,2-bis(4-hydroxyphenyl)ethane], oxidative dechlorination of the side chain proceeded, and monophenolic carboxylic acid accumulated, followed by the formation of multiple unidentified polar degradation products. The breakdown proceeded more rapidly when reductively dechlorinated (dichloro-form) methoxychlor was applied as the initial substrate. The resultant carboxylic acids and polar degradation products are likely further biodegraded by ubiquitous bacteria. The isolate possibly plays an important role for complete degradation (mineralization) of methoxychlor by providing the readily biodegradable substrates.

  20. Phe120 contributes to the regiospecificity of cytochrome P450 2D6: mutation leads to the formation of a novel dextromethorphan metabolite.

    PubMed Central

    Flanagan, Jack U; Maréchal, Jean-Didier; Ward, Richard; Kemp, Carol A; McLaughlin, Lesley A; Sutcliffe, Michael J; Roberts, Gordon C K; Paine, Mark J I; Wolf, C Roland

    2004-01-01

    Although the residues that determine the preference of CYP2D6 (cytochrome P450 2D6) for compounds containing a basic nitrogen are well characterized, the contribution of other active site residues to substrate binding and orientation is less well understood. Our structural model of CYP2D6 identifies the aromatic residue Phe120 as a likely major feature of the active site. To examine the role of Phe120, mutants of CYP2D6 in which this residue has been substituted by alanine, leucine, tyrosine, serine, histidine, tryptophan or methionine residues have been prepared in bacterial membranes co-expressing human cytochrome NADPH cytochrome P450 oxidoreductase. The mutants have been characterized using the prototypical bufuralol 1' hydroxylase and dextromethorphan O- and N-demethylase activities of CYP2D6. Larger effects on K(m) values are observed for dextromethorphan O-demethylation than for bufuralol 1' hydroxylation, indicating that the Phe120 side chain is more important in dextromethorphan than in bufuralol binding. A role for this side chain in determining the regiospecificity of substrate oxidation was indicated by changes in the relative rates of O- and N-demethylation of dextromethorphan and, notably, by the formation of 7-hydroxy dextromethrophan, a novel dextromethorphan metabolite, in mutants in which it had been substituted. Computational studies of dextromethorphan binding to the active site of the Phe120-->Ala mutant were carried out to throw light on the way in which the removal of this side chain leads to different modes of ligand binding. PMID:14992686

  1. Pharmacokinetic Effects of Isavuconazole Coadministration With the Cytochrome P450 Enzyme Substrates Bupropion, Repaglinide, Caffeine, Dextromethorphan, and Methadone in Healthy Subjects.

    PubMed

    Yamazaki, Takao; Desai, Amit; Goldwater, Ronald; Han, David; Howieson, Corrie; Akhtar, Shahzad; Kowalski, Donna; Lademacher, Christopher; Pearlman, Helene; Rammelsberg, Diane; Townsend, Robert

    2017-01-01

    This report describes phase 1 clinical trials performed to assess interactions of oral isavuconazole at the clinically targeted dose (200 mg, administered as isavuconazonium sulfate 372 mg, 3 times a day for 2 days; 200 mg once daily [QD] thereafter) with single oral doses of the cytochrome P450 (CYP) substrates: bupropion hydrochloride (CYP2B6; 100 mg; n = 24), repaglinide (CYP2C8/CYP3A4; 0.5 mg; n = 24), caffeine (CYP1A2; 200 mg; n = 24), dextromethorphan hydrobromide (CYP2D6/CYP3A4; 30 mg; n = 24), and methadone (CYP2B6/CYP2C19/CYP3A4; 10 mg; n = 23). Compared with each drug alone, coadministration with isavuconazole changed the area under the concentration-time curves (AUC∞ ) and maximum concentrations (Cmax ) as follows: bupropion, AUC∞ reduced 42%, Cmax reduced 31%; repaglinide, AUC∞ reduced 8%, Cmax reduced 14%; caffeine, AUC∞ increased 4%, Cmax reduced 1%; dextromethorphan, AUC∞ increased 18%, Cmax increased 17%; R-methadone, AUC∞ reduced 10%, Cmax increased 3%; S-methadone, AUC∞ reduced 35%, Cmax increased 1%. In all studies, there were no deaths, 1 serious adverse event (dextromethorphan study; perioral numbness, numbness of right arm and leg), and adverse events leading to study discontinuation were rare. Thus, isavuconazole is a mild inducer of CYP2B6 but does not appear to affect CYP1A2-, CYP2C8-, or CYP2D6-mediated metabolism.

  2. Cytochrome P4502D6 catalyzes the O-demethylation of the psychoactive alkaloid ibogaine to 12-hydroxyibogamine.

    PubMed

    Obach, R S; Pablo, J; Mash, D C

    1998-08-01

    Ibogaine is a psychoactive alkaloid that possesses potential as an agent to treat opiate and cocaine addiction. The primary metabolite arises via O-demethylation at the 12-position to yield 12-hydroxyibogamine. In this report, evidence is presented that the O-demethylation of ibogaine observed in human hepatic microsomes is catalyzed primarily by the polymorphically expressed cytochrome P-4502D6 (CYP2D6). An enzyme kinetic examination of ibogaine O-demethylase activity in pooled human liver microsomes suggested that two (or more) enzymes are involved in this reaction: one with a low KMapp (1.1 microM) and the other with a high KMapp (>200 microM). The low KMapp activity comprised >95% of total intrinsic clearance. Human liver microsomes from three individual donors demonstrated similar enzyme kinetic parameters (mean KMapp = 0.55 +/- 0.09 microM and 310 +/- 10 microM for low and high KM activities, respectively). However, a fourth human microsome sample that appeared to be a phenotypic CYP2D6 poor metabolizer possessed only the high KMapp activity. In hepatic microsomes from a panel of human donors, the low KMapp ibogaine O-demethylase activity correlated with CYP2D6-catalyzed bufuralol 1'-hydroxylase activity but not with other P450 isoform-specific activities. Quinidine, a CYP2D6-specific inhibitor, inhibited ibogaine O-demethylase (IC50 = 0.2 microM), whereas other P450 isoform-specific inhibitors did not inhibit this activity. Also, of a battery of recombinant heterologously expressed human P450 isoforms, only rCYP2D6 possessed significant ibogaine O-demethylase activity. Thus, it is concluded that ibogaine O-demethylase is catalyzed by CYP2D6 and that this isoform is the predominant enzyme of ibogaine O-demethylation in humans. The potential pharmacological implications of these findings are discussed.

  3. The continuous kinetic determination of p-nitroanisole O-demethylation in hemoglobin-free perfused rat liver.

    PubMed

    Thurman, R G; Marazzo, D P; Jones, L S; Kauffman, F C

    1977-05-01

    P-Nitroanisole O-demethylation by perfused rat liver based on the spectral properties of the product, p-nitrophenolate, was determined continuously. Rates of p-nitrophenol production in this system were sensitive to inhibition by CO. p-Nitrophenolate production by livers of normal animals was linear for up to 30 minutes; however, rates were only linear for 1 to 2 minutes followed by a steady decline in induced (6-fold) livers from phenobarbital-treated rats. Only a small portion (24%) of this steady decline could be accounted for by the formation of conjugation products. Additionally, infusion of p-nitrophenol (14 micronM) was not associated with a decline in rate. The decline in rate in induced livers was reversed by glucose, suggesting that an intimate relationship may exist between drug and carbohydrate metabolism in the intact liver. Alteration in rates of p-nitroanisole metabolism with various inducing agents of the mixed-function oxidation system (phenobarbital; ethanol) produced parallel changes in rates of hepatic lactate production, most likely reflecting the aciton of p-nitrophenol to uncouple oxidative phosphorylation. The data support the hypothesis that the decline in rate in p-nitroanisole O-demethylation in livers from phenobarbital-treated rats is due to reduced availability of NADPH for mixed-function oxidation.

  4. H(2)-CO(2)-Dependent Anaerobic O-Demethylation Activity in Subsurface Sediments and by an Isolated Bacterium.

    PubMed

    Liu, S; Suflita, J M

    1993-05-01

    The ability of microorganisms in sediments from the Atlantic Coastal Plain to biodegrade methoxylated aromatic compounds was examined. O-demethylation activity was detected in deep (121- and 406-m) sediments, as well as in the surface soil. A syringate-demethylating consortium, containing at least three types of bacteria, was enriched from a deep-sediment sample in a medium containing syringate as the sole organic carbon source and with a N(2)-CO(2) atmosphere. An isolate which demethylated syringate was obtained from the enrichment on an agar medium incubated under a H(2)-CO(2) but not a N(2)-CO(2) or N(2) atmosphere. O demethylation of syringate of this isolate was dependent on the presence of both H(2) and CO(2) in the gas phase. The metabolism of syringate occurred in a sequential manner: methylgallate accumulated transiently before it was converted to gallate. Mass balance analysis suggests that the stoichiometry of the reaction in this isolate proceeds in accordance with the following generalized equation: C(7)H(3)O(3)(OCH(3))(n) + nHCO(3) + nH(2) --> C(7)H(3)O(3)(OH)(n) + nCH(3)COO + nH(2)O.

  5. Effects of the Chinese herbal formula "Zuojin Pill" on the pharmacokinetics of dextromethorphan in healthy Chinese volunteers with CYP2D6*10 genotype.

    PubMed

    Qiu, Furong; Liu, Songcan; Miao, Ping; Zeng, Jin; Zhu, Leilei; Zhao, TongFang; Ye, Yujie; Jiang, Jian

    2016-06-01

    Zuojin Pill has been shown to inhibit the cytochrome P450 (CYP) 2D6 isoenzyme in vitro. In Chinese individuals, CYP 2D6*10 is the most common allele with reduced enzyme activity. In this study, we investigated the pharmacokinetic interaction between Zuojin Pill and the sensitive CYP2D6 probe dextromethorphan in healthy Chinese volunteers with CYP2D6*10 genotype. A pharmacokinetics interaction study was carried out in three groups with CYP2D6*1/*1 (n = 6), CYP2D6*1/*10 (n = 6), and CYP2D6*10/*10 (n = 6) genotypes. Each participant received a single oral dose of dextromethorphan (15 mg) followed by Zuojin Pill (3 g twice daily) for 7 days, and received 3 g Zuojin Pill with 15 mg dextromethorphan in the last day. Blood samples (0-24 h) and urine samples (0-12 h) were collected at baseline and after the administration of Zuojin Pill, and the samples' concentration of dextromethorphan and its main metabolite dextrorphan was determined. Compared to baseline values, co-administration of Zuojin Pill (3 g twice daily) for 7 days increased the AUC0-24 of dextromethorphan [mean (90 % CI)] by 3.00-fold (2.49∼3.61) and 1.71-fold (1.42∼2.06), and decreased oral clearance(CL/F) by 0.27-fold (0.2-0.40) and 0.57-fold (0.48-0.67) in the participants with CYP2D6*1/*1 and CYP2D6*1/*10 genotypes, respectively. In contrast, no significant change was observed in these pharmacokinetic parameters of the participants with CYP2D6*10/*10 genotype. These data demonstrated that administration of Zuojin Pill inhibited moderately CYP2D6-mediated metabolism of dextromethorphan in healthy volunteers. The inhibitory influence of CYP2D6 was greater in CYP2D6*1/*1 and CYP2D6*1/*10 groups than CYP2D6 *10/*10 group.

  6. The Roles of a Flavone-6-Hydroxylase and 7-O-Demethylation in the Flavone Biosynthetic Network of Sweet Basil*

    PubMed Central

    Berim, Anna; Gang, David R.

    2013-01-01

    Lipophilic flavonoids found in the Lamiaceae exhibit unusual 6- and 8-hydroxylations whose enzymatic basis is unknown. We show that crude protein extracts from peltate trichomes of sweet basil (Ocimum basilicum L.) cultivars readily hydroxylate position 6 of 7-O-methylated apigenin but not apigenin itself. The responsible protein was identified as a P450 monooxygenase from the CYP82 family, a family not previously reported to be involved in flavonoid metabolism. This enzyme prefers flavones but also accepts flavanones in vitro and requires a 5-hydroxyl in addition to a 7-methoxyl residue on the substrate. A peppermint (Mentha × piperita L.) homolog displayed identical substrate requirements, suggesting that early 7-O-methylation of flavones might be common in the Lamiaceae. This hypothesis is further substantiated by the pioneering discovery of 2-oxoglutarate-dependent flavone demethylase activity in basil, which explains the accumulation of 7-O-demethylated flavone nevadensin. PMID:23184958

  7. Dextromethorphan/quinidine: in pseudobulbar affect.

    PubMed

    Garnock-Jones, Karly P

    2011-05-01

    Pseudobulbar affect is characterized by uncontrollable, inappropriate laughing and/or crying that is either unrelated or out of proportion to the emotions felt by the patient and occurs in patients with neurological disorders, such as amyotrophic lateral sclerosis (ALS), multiple sclerosis or traumatic brain injury. Dextromethorphan/quinidine is indicated in the US for the treatment of pseudobulbar affect. Dextromethorphan, when its metabolism is inhibited by the coadministration of quinidine, has been shown to have a positive effect on the symptoms of pseudobulbar affect. Dextromethorphan/quinidine 20 mg/10 mg twice daily was associated with a significantly greater decrease in the rate of pseudobulbar affect episodes per day (primary endpoint) than placebo in the 12-week, randomized, double-blind, placebo-controlled, multicentre STAR trial (Safety, Tolerability, And efficacy Results trial of AVP-923 in PBA [pseudobulbar affect]) involving patients with pseudobulbar affect and ALS or multiple sclerosis. Moreover, the mean change from baseline in Center for Neurologic Study-Lability Scale score at 12 weeks was significantly greater among recipients of dextromethorphan/quinidine 20 mg/10 mg twice daily than those receiving placebo. Dextromethorphan/quinidine 20 mg/10 mg twice daily was generally well tolerated. The drug has been shown to cause dosage-dependent corrected QT interval (QTc) prolongation; however, in the STAR trial, dextromethorphan/quinidine 20 mg/10 mg twice daily appeared to be well tolerated with regard to QTc prolongation.

  8. Molecular analysis of the dmpM gene encoding an O-demethyl puromycin O-methyltransferase from Streptomyces alboniger.

    PubMed

    Lacalle, R A; Ruiz, D; Jiménez, A

    1991-12-20

    The nucleotide (nt) sequence of a 1332-bp fragment of Streptomyces alboniger DNA containing the gene (dmpM), which encodes an O-demethyl puromycin O-methyltransferase (DMPM), has been determined. The dmpM gene contains a 1131-nt open reading frame which encodes a polypeptide of Mr 40,303; this is consistent with the 44 +/- 2.5- and 160-kDa sizes of the DMPM monomer and its native form, respectively. The ATG start codon of dmpM is 50 bp downstream from the coding sequence of the gene (pac), which determines a puromycin N-acetyltransferase. S1 mapping experiments indicate that pac and dmpM are transcribed on a single transcript, which ends at least 500 nt downstream from the dmpM stop codon. The deduced amino acid sequence of DMPM shows significant similarities to those of a hydroxyindole O-methyltransferase, which is involved in the biosynthesis of melatonin by bovine pineal glands [Ishida et al., J. Biol. Chem. 262 (1987) 2895-2899], a hydroxyneurosporene methyltransferase, which is involved in carotenoid biosynthesis in the purple nonsulfur bacterium, Rhodobacter capsulatus [Armstrong et al., Mol. Gen. Genet. 216 (1989) 254-268] and two O-methyltransferases of the tetracenomycin biosynthesis pathway from Streptomyces glaucescens.

  9. Dioxygenases catalyze O-demethylation and O,O-demethylenation with widespread roles in benzylisoquinoline alkaloid metabolism in opium poppy.

    PubMed

    Farrow, Scott C; Facchini, Peter J

    2013-10-04

    In opium poppy, the antepenultimate and final steps in morphine biosynthesis are catalyzed by the 2-oxoglutarate/Fe(II)-dependent dioxygenases, thebaine 6-O-demethylase (T6ODM) and codeine O-demethylase (CODM). Further investigation into the biochemical functions of CODM and T6ODM revealed extensive and unexpected roles for such enzymes in the metabolism of protopine, benzo[c]phenanthridine, and rhoeadine alkaloids. When assayed with a wide range of benzylisoquinoline alkaloids, CODM, T6ODM, and the functionally unassigned paralog DIOX2, renamed protopine O-dealkylase, showed novel and efficient dealkylation activities, including regio- and substrate-specific O-demethylation and O,O-demethylenation. Enzymes catalyzing O,O-demethylenation, which cleave a methylenedioxy bridge leaving two hydroxyl groups, have previously not been reported in plants. Similar cleavage of methylenedioxy bridges on substituted amphetamines is catalyzed by heme-dependent cytochromes P450 in mammals. Preferred substrates for O,O-demethylenation by CODM and protopine O-dealkylase were protopine alkaloids that serve as intermediates in the biosynthesis of benzo[c]phenanthridine and rhoeadine derivatives. Virus-induced gene silencing used to suppress the abundance of CODM and/or T6ODM transcripts indicated a direct physiological role for these enzymes in the metabolism of protopine alkaloids, and they revealed their indirect involvement in the formation of the antimicrobial benzo[c]phenanthridine sanguinarine and certain rhoeadine alkaloids in opium poppy.

  10. Dioxygenases Catalyze O-Demethylation and O,O-Demethylenation with Widespread Roles in Benzylisoquinoline Alkaloid Metabolism in Opium Poppy*

    PubMed Central

    Farrow, Scott C.; Facchini, Peter J.

    2013-01-01

    In opium poppy, the antepenultimate and final steps in morphine biosynthesis are catalyzed by the 2-oxoglutarate/Fe(II)-dependent dioxygenases, thebaine 6-O-demethylase (T6ODM) and codeine O-demethylase (CODM). Further investigation into the biochemical functions of CODM and T6ODM revealed extensive and unexpected roles for such enzymes in the metabolism of protopine, benzo[c]phenanthridine, and rhoeadine alkaloids. When assayed with a wide range of benzylisoquinoline alkaloids, CODM, T6ODM, and the functionally unassigned paralog DIOX2, renamed protopine O-dealkylase, showed novel and efficient dealkylation activities, including regio- and substrate-specific O-demethylation and O,O-demethylenation. Enzymes catalyzing O,O-demethylenation, which cleave a methylenedioxy bridge leaving two hydroxyl groups, have previously not been reported in plants. Similar cleavage of methylenedioxy bridges on substituted amphetamines is catalyzed by heme-dependent cytochromes P450 in mammals. Preferred substrates for O,O-demethylenation by CODM and protopine O-dealkylase were protopine alkaloids that serve as intermediates in the biosynthesis of benzo[c]phenanthridine and rhoeadine derivatives. Virus-induced gene silencing used to suppress the abundance of CODM and/or T6ODM transcripts indicated a direct physiological role for these enzymes in the metabolism of protopine alkaloids, and they revealed their indirect involvement in the formation of the antimicrobial benzo[c]phenanthridine sanguinarine and certain rhoeadine alkaloids in opium poppy. PMID:23928311

  11. Intramolecular Oxidative O-Demethylation of an Oxoferryl Porphyrin Complexed with a Per-O-methylated β-Cyclodextrin Dimer.

    PubMed

    Kitagishi, Hiroaki; Kurosawa, Shun; Kano, Koji

    2016-11-22

    The intramolecular oxidation of ROCH3 to ROCH2 OH, where the latter compound spontaneously decomposed to ROH and HCHO, was observed during the reaction of the supramolecular complex (met-hemoCD3) with cumene hydroperoxide in aqueous solution. Met-hemoCD3 is composed of meso-tetrakis(4-sulfonatophenyl)porphinatoiron(III) (Fe(III) TPPS) and a per-O-methylated β-cyclodextrin dimer having an -OCH2 PyCH2 O- linker (Py=pyridine-3,5-diyl). The O=Fe(IV) TPPS complex was formed by the reaction of met-hemoCD3 with cumene hydroperoxide, and isolated by gel-filtration chromatography. Although the isolated O=Fe(IV) TPPS complex in the cyclodextrin cage was stable in aqueous solution at 25 °C, it was gradually converted to Fe(II) TPPS (t1/2 =7.6 h). This conversion was accompanied by oxidative O-demethylation of an OCH3 group in the cyclodextrin dimer. The results indicated that hydrogen abstraction by O=Fe(IV) TPPS from ROCH3 yields HO-Fe(III) TPPS and ROCH2(.) . This was followed by radical coupling to afford Fe(II) TPPS and ROCH2 OH. The hemiacetal (ROCH2 OH) immediately decomposed to ROH and HCHO. This study revealed the ability of oxoferryl porphyrin to induce two-electron oxidation. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Myoclonus after dextromethorphan administration in peritoneal dialysis.

    PubMed

    Tanaka, Akio; Nagamatsu, Tadashi; Yamaguchi, Makoto; Nomura, Atsushi; Nagura, Fumiko; Maeda, Kayaho; Tomino, Tatsuhito; Watanabe, Tatsuhito; Shimizu, Hideaki; Fujita, Yoshiro; Ito, Yasuhiko

    2011-01-01

    To report a case of myoclonus that developed after administration of dextromethorphan. A 64-year-old man was diagnosed with chronic renal failure due to diabetic nephropathy. The patient started on peritoneal dialysis 6 months before he was hospitalized. Two days before hospitalization, he developed cough and sputum and he visited an outpatient clinic, where dextromethorphan was prescribed. After taking a total of 30 mg of dextromethorphan, the patient developed myoclonus, tremor, agitation, slurred speech, and diaphoresis, which continued after he stopped taking the prescribed medicine. He visited an emergency department and was hospitalized for examination and treatment of myoclonus. As the patient's dialysis schedule was adequate, these symptoms were likely not due to uremia. The blood concentration of dextromethorphan (2.68 ng/mL) 60 hours after the 30-mg dose was higher than expected, and the blood concentration of dextrorphan, a metabolite, was lower than expected. We suspected that myoclonus was due to dextromethorphan-related symptoms induced by CYP2D6, which primarily metabolizes dextromethorphan. We analyzed the CYP2D6 gene for polymorphisms and identified CYP2D6 (*)1/(*)10. The patient had been taking metoprolol 40 mg/day for 2 years. The blood concentration of metoprolol 6 hours after administration was 13 ng/mL, which suggests that it was metabolized normally. Metoprolol has another metabolic pathway, via CYP2C19, and this may have led to its lack of accumulation. Moreover, metoprolol may have bound to active CYP2D6. Thus, affinity for CYP2D6, protein-binding rate, and lipid solubility may influence these drug interactions. Total scores for the Adverse Drug Reaction (ADR) probability scale and the Drug Interaction Probability Scale (DIPS) were 9 (highly probable) and 3 (possible), respectively. Myoclonus and other symptoms in this patient may have been caused by a prolonged high concentration of dextromethorphan due to CYP2D6 polymorphisms and drug

  13. Dextromethorphan and quinidine combination for heroin detoxification.

    PubMed

    Akerele, Evaristo; Bisaga, Adam; Sullivan, Maria A; Garawi, Fatima; Comer, Sandra D; Thomas, Anil A; Nunes, Edward V; Kleber, Herbert D

    2008-01-01

    Dextromethorphan (DM) is a low-affinity, non-competitive NMDA receptor antagonist that has shown promise in preclinical and preliminary clinical studies for the reduction of opioid withdrawal symptoms, but when used at higher doses, it is associated with deleterious side effects attributed to its metabolite, dextrorphan. A clinical trial was therefore conducted to test the withdrawal-suppressant effect of a combination of dextromethorphan with quinidine (DM/Q). Quinidine inhibits the metabolism of dextromethorphan, reducing dextrorphan levels. Opioid-dependent patients were admitted to an inpatient unit, stabilized for three days on morphine (25 mg, sc, every six hours), and randomly assigned on day 2 to DM/Q (30 mg/30 mg, twice a day) (n = 22) or matching placebo (n = 9) prior to the discontinuation of morphine on day 4. Withdrawal symptoms, measured with the Modified Himmelsbach Opioid Withdrawal Scale (MHOWS), increased significantly on days 4 and 5 (Z = 3.70, p = .0002), and by day 6, 90% of the sample (28/31) had dropped out of the study. There were no differences between treatment groups on either outcome measure. The combination of dextromethorphan and quinidine appears ineffective as a primary treatment for opioid withdrawal. Future studies should examine dextromethorphan as an adjunct to other anti-withdrawal medications and focus more on the relationship between dextrorphan levels and withdrawal suppression.

  14. Dextromethorphan and Quinidine Combination for Heroin Detoxification

    PubMed Central

    Akerele, Evaristo; Bisaga, Adam; Sullivan, Maria A.; Garawi, Fatima; Comer, Sandra D.; Thomas, Anil A.; Nunes, Edward V.; Kleber, Herbert D.

    2015-01-01

    Dextromethorphan (DM) is a low-affinity, non-competitive NMDA receptor antagonist that has shown promise in pre-clinical and preliminary clinical studies for the reduction of opioid withdrawal symptoms, but when used at higher doses, it is associated with deleterious side effects attributed to its metabolite, dextrorphan. A clinical trial was therefore conducted to test the withdrawal-suppressant effect of a combination of dextromethorphan with quinidine (DM/Q). Quinidine inhibits the metabolism of dextromethorphan, reducing dextrorphan levels. Opioid-dependent patients were admitted to an inpatient unit, stabilized for three days on morphine (25 mg, sc, every six hours), and randomly assigned on day 2 to DM/Q (30 mg/30 mg, twice a day) (n = 22) or matching placebo (n = 9) prior to the discontinuation of morphine on day 4. Withdrawal symptoms, measured with the Modified Himmelsbach Opioid Withdrawal Scale (MHOWS), increased significantly on days 4 and 5 (Z = 3.70, p = .0002), and by day 6, 90% of the sample (28/31) had dropped out of the study. There were no differences between treatment groups on either outcome measure. The combination of dextromethorphan and quinidine appears ineffective as a primary treatment for opioid withdrawal. Future studies should examine dextromethorphan as an adjunct to other anti-withdrawal medications and focus more on the relationship between dextrorphan levels and withdrawal suppression. PMID:18463993

  15. Tramadol, but not its major metabolite (mono-O-demethyl tramadol) depresses compound action potentials in frog sciatic nerves

    PubMed Central

    Katsuki, R; Fujita, T; Koga, A; Liu, T; Nakatsuka, T; Nakashima, M; Kumamoto, E

    2006-01-01

    Background and purpose: Although tramadol is known to exhibit a local anaesthetic effect, how tramadol exerts this effect is not understood fully. Experimental approach: The effects of tramadol and its metabolite mono-O-demethyl-tramadol (M1) on compound action potentials (CAPs) were examined by applying the air-gap method to frog sciatic nerves, and the results were compared with those of other local anaesthetics, lidocaine and ropivacaine. Key results: Tramadol reduced the peak amplitude of the CAP in a dose-dependent manner (IC50=2.3 mM). On the other hand, M1 (1–2 mM), which exhibits a higher affinity for μ-opioid receptors than tramadol, did not affect CAPs. These effects of tramadol were resistant to the non-selective opioid receptor antagonist naloxone and the μ-opioid receptor agonist, DAMGO, did not affect CAPs. This tramadol action was not affected by a combination of the noradrenaline uptake inhibitor, desipramine, and the 5-hydroxytryptamine uptake inhibitor, fluoxetine. Lidocaine and ropivacaine also concentration-dependently reduced CAP peak amplitudes with IC50 values of 0.74 and 0.34 mM, respectively. Conclusions and implications: These results indicate that tramadol reduces the peak amplitude of CAP in peripheral nerve fibres with a potency which is less than those of lidocaine and ropivacaine, whereas M1 has much less effect on CAPs. This action of tramadol was not produced by activation of μ-opioid receptors nor by inhibition of noradrenaline and 5-hydroxytryptamine uptake. It is suggested that the methyl group present in tramadol but not in M1 may play an important role in producing nerve conduction block. PMID:16921387

  16. Identification of human cytochrome P450 2D6 as major enzyme involved in the O-demethylation of the designer drug p-methoxymethamphetamine.

    PubMed

    Staack, Roland F; Theobald, Denis S; Paul, Liane D; Springer, Dietmar; Kraemer, Thomas; Maurer, Hans H

    2004-04-01

    p-Methoxymethamphetamine (PMMA) is a new designer drug, listed in many countries as a controlled substance. Several fatalities have been attributed to the abuse of this designer drug. Previous in vivo studies using Wistar rats had shown that PMMA was metabolized mainly by O-demethylation. The aim of the study presented here was to identify the human hepatic cytochrome P450 (P450) enzymes involved in the biotransformation of PMMA to p-hydroxymethamphetamine. Baculovirus-infected insect cell microsomes, pooled human liver microsomes (pHLMs), and CYP2D6 poor-metabolizer genotype human liver microsomes (PM HLMs) were used for this purpose. Only CYP2D6 catalyzed O-demethylation. The apparent K(m) and V(max) values in baculovirus-infected insect cell microsomes were 4.6 +/- 1.0 microM and 92.0 +/- 3.7 pmol/min/pmol P450, respectively, and 42.0 +/- 4.0 microM and 412.5 +/- 10.8 pmol/min/mg protein in pHLMs. Inhibition studies with 1 microM quinidine showed significant inhibition of the metabolite formation (67.2 +/- 0.6%; p < 0.0001), and comparison of the metabolite formation between pHLMs and PM HLMs revealed significantly lower metabolite formation in the incubations with PM HLMs (87.3 +/- 1.1%; p < 0.0001). According to these studies, CYP2D6 is the major P450 involved in O-demethylation of PMMA.

  17. Environmental significance of O-demethylation of chloroanisoles by soil bacterial isolates as a mechanism that improves the overall biodegradation of chlorophenols.

    PubMed

    Goswami, Mandira; Recio, Eliseo; Campoy, Sonia; Martín, Juan Francisco; Coque, Juan-José R

    2007-10-01

    The biodegradation rate of chlorophenols in the environment seems to be limited by a competitive mechanism of O-methylation which produces chloroanisoles with a high potential of being bioconcentrated in living organisms. In this work we report for the first time the isolation of three soil bacterial strains able to efficiently degrade 2,4,6-trichloroanisole (2,4,6-TCA). These strains were identified as Xanthomonas retroflexus INBB4, Pseudomonas putida INBP1 and Acinetobacter radioresistens INBS1. In these isolates 2,4,6-TCA was efficiently metabolized in a minimal medium containing methanol and 2,4,6-TCA as the only carbon sources, with a concomitant release of 3 mol of chloride ion from 1 mol of 2,4,6-TCA, indicating complete dehalogenation of 2,4,6-TCA. 2,4,6-trichlorophenol (2,4,6-TCP) was identified as a degradative intermediate, indicating that 2,4,6-TCA underwent O-demethylation as the first step in the biodegradation process. 2,4,6-TCP was further transformed into 2,6-dichloro-para-hydroquinone (2,6-DCHQ) and subsequently mineralized. The degradation of chloroanisoles could improve the overall biodegradation of chlorophenols in the environment, because those chlorophenols previously biomethylated might also be later biodegraded. Xanthomonas retroflexus INBB4 has two O-demethylation systems: one is an oxygenase-type demethylase, and the other is a tetrahydrofolate (THF)-dependent O-demethylase. On the contrary O-demethylation of 2,4,6-TCA in P. putida INBP1 is just catalysed by an oxygenase-type NADH/NADPH-dependent O-demethylase, whereas in A. radioresistens INBS1 a THF-dependent O-demethylase activity was detected.

  18. Trial of Naltrexone and Dextromethorphan for Gulf War Veterans Illnesses

    DTIC Science & Technology

    2011-07-01

    W81XWH-09-2-0065 TITLE: Trial of Naltrexone and Dextromethorphan for Gulf War Veterans Illnesses PRINCIPAL INVESTIGATOR: William J. Meggs, MD...2011 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illness 5b. GRANT NUMBER W81XWH-09...that many with Gulf War Illness could enter either the naltrexone or dextromethorphan arm but not both. We are applying to allow subjects to enter

  19. Adverse events associated with pediatric exposures to dextromethorphan.

    PubMed

    Paul, Ian M; Reynolds, Kate M; Kauffman, Ralph E; Banner, William; Bond, G Randall; Palmer, Robert B; Burnham, Randy I; Green, Jody L

    2017-01-01

    Dextromethorphan is the most common over-the-counter (OTC) antitussive medication. We sought to characterize adverse events associated with dextromethorphan in children <12 years old from a surveillance program of OTC cough/cold medication exposures. This is a retrospective case series of oral exposures to dextromethorphan with ≥1 adverse event from multiple U.S. sources (National Poison Data System, FDA Adverse Event Reporting System, manufacturer safety reports, news/media, medical literature) reported between 2008 and 2014. An expert panel determined the relationship between exposure and adverse events, estimated dose ingested, intent of exposure, and identified contributing factors to exposure. 1716 cases contained ≥1 adverse event deemed at least potentially related to dextromethorphan; 1417 were single product exposures. 773/1417 (55%) involved only one single-ingredient dextromethorphan product (dextromethorphan-only). Among dextromethorphan-only cases, 3% followed ingestion of a therapeutic dose; 78% followed an overdose. 69% involved unsupervised self-administration and 60% occurred in children <4 years old. No deaths or pathologic dysrhythmias occurred. Central nervous system [e.g., ataxia (N = 420)] and autonomic symptoms [e.g., tachycardia (N = 224)] were the most common adverse events. Flushing and/or urticarial rash occurred in 18.1% of patients. Dystonia occurred in 5.4%. No fatalities were identified in this multifaceted surveillance program following a dextromethorphan-only ingestion. Adverse events were predominantly associated with overdose, most commonly affecting the central nervous and autonomic systems.

  20. Effects of 22 Novel CYP2D6 Variants Found in the Chinese Population on the Bufuralol and Dextromethorphan Metabolisms In Vitro.

    PubMed

    Cai, Jie; Dai, Da-Peng; Geng, Pei-Wu; Wang, Shuang-Hu; Wang, Hao; Zhan, Yun-Yun; Huang, Xiang-Xin; Hu, Guo-Xin; Cai, Jian-Ping

    2016-03-01

    Cytochrome P450 2D6 (CYP2D6) is a highly polymorphic enzyme that metabolizes a large number of therapeutic drugs. To date, more than 100 CYP2D6 allelic variants have been reported. Among these variants, we recently identified 22 novel variants in the Chinese population. The aim of this study was to functionally characterize the enzymatic activity of these variants in vitro. A baculovirus-mediated expression system was used to express wild-type CYP2D6.1 and other variants (CYP2D6.2, CYP2D6.10 and 22 novel CYP2D6 variants) at high levels. Then, the insect microsomes containing expressed CYP2D6 proteins were incubated with bufuralol or dextromethorphan at 37°C for 20 or 25 min., respectively. After termination, the metabolites were extracted and used for the detection with high-performance liquid chromatography. Among the 24 CYP2D6 variants tested, two variants (CYP2D6.92 and CYP2D6.96) were found to be catalytically inactive. The remaining 22 variants exhibited significantly decreased intrinsic clearance values for bufuralol 1'-hydroxylation and 20 variants showed significantly lower intrinsic clearance values for dextromethorphan O-demethylation than those of the wild-type CYP2D6.1. Our in vitro results suggest that most of the variants exhibit significantly reduced catalytic activities compared with the wild-type, and these data provide valuable information for personalized medicine in Chinese and other Asian populations. © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  1. The dextromethorphan analog dimemorfan attenuates kainate-induced seizures via σ1 receptor activation: comparison with the effects of dextromethorphan

    PubMed Central

    Shin, Eun-Joo; Nah, Seung-Yeol; Kim, Won-Ki; Ko, Kwang Ho; Jhoo, Wang-Kee; Lim, Yong-Kwang; Cha, Joo Young; Chen, Chieh-Fu; Kim, Hyoung-Chun

    2005-01-01

    In a previous study, we demonstrated that a dextromethorphan analog, dimemorfan, has neuroprotective effects. Dextromethorphan and dimemorfan are high-affinity ligands at σ1 receptors. Dextromethorphan has moderate affinities for phencyclidine sites, while dimemorfan has very low affinities for such sites, suggesting that these sites are not essential for the anticonvulsant actions of dimemorfan. Kainate (KA) administration (10 mg kg−1, i.p.) produced robust convulsions lasting 4–6 h in rats. Pre-treatment with dimemorfan (12 or 24 mg kg−1) reduced seizures in a dose-dependent manner. Dimemorfan pre-treatment also attenuated the KA-induced increases in c-fos/c-jun expression, activator protein (AP)-1 DNA-binding activity, and loss of cells in the CA1 and CA3 fields of the hippocampus. These effects of dimemorfan were comparable to those of dextromethorphan. The anticonvulsant action of dextromethorphan or dimemorfan was significantly counteracted by a selective σ1 receptor antagonist BD 1047, suggesting that the anticonvulsant action of dextromethorphan or dimemorfan is, at least in part, related to σ1 receptor-activated modulation of AP-1 transcription factors. We asked whether dimemorfan produces the behavioral side effects seen with dextromethorphan or dextrorphan (a phencyclidine-like metabolite of dextromethorphan). Conditioned place preference and circling behaviors were significantly increased in mice treated with phencyclidine, dextrorphan or dextromethorphan, while mice treated with dimemorfan showed no behavioral side effects. Our results suggest that dimemorfan is equipotent to dextromethorphan in preventing KA-induced seizures, while it may lack behavioral effects, such as psychotomimetic reactions. PMID:15723099

  2. Serum metabolic changes in rats after intragastric administration of dextromethorphan.

    PubMed

    Bao, Shihui; Zhang, Jing; Lin, Zixia; Su, Ke; Mo, Jingjing; Hong, Lin; Qian, Shuyi; Chen, Lianguo; Sun, Fa; Wen, Congcong; Wu, Qing; Hu, Lufeng; Lin, Guanyang; Wang, Xianqin

    2017-03-01

    Dextromethorphan is recognized as a substance of abuse around the world. An estimated 3.1 million people between the ages of 12 and 25 years (5.3%) misused over-the-counter cough and cold medications in 2006. In this study, we developed a serum metabolomic method by gas chromatography-mass spectrometry (GC-MS) to evaluate the effect of abuse of dextromethorphan on rats. The dextromethorphan-treated rats were given 12, 24 and 48 mg/kg (low, medium, high) of dextromethorphan by intragastric administration each day for 3 days. Partial least squares-discriminate analysis revealed that intragastric administration of dextromethorphan induced metabolic perturbations. Compared with the control (healthy) group, the levels of propanoic acid, urea, heptafluorobutanoic acid, 2-hexyldecanoic acid and butanedioic acid of the low group decreased; levels of propanoic acid and heptafluorobutanoic acid of the medium group decreased, while that of benzoic acid increased; and levels of 2-hexyldecanoic acid, glycerol and butanedioic acid of the high group increased. These biomarkers are involved in the citric acid cycle, urea cycle, glycerolipid metabolism and tricarboxylic acid cycle. The results indicate that the metabolomic method by GC-MS may be useful to elucidate abuse of dextromethorphan. According to the pathological changes in the liver at different dosages, dextromethorphan is not hepatotoxic after intragastric administration of 12, 24 and 48 mg/kg for 3 days. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Developmental toxicity of dextromethorphan in zebrafish embryos/larvae.

    PubMed

    Xu, Zheng; Williams, Frederick E; Liu, Ming-Cheh

    2011-03-01

    Dextromethorphan is widely used in over-the-counter cough and cold medications. Its efficacy and safety for infants and young children remains to be clarified. The present study was designed to use zebrafish as a model to investigate the potential toxicity of dextromethorphan during embryonic and larval development. Three sets of zebrafish embryos/larvae were exposed to dextromethorphan at 24, 48 and 72 h post fertilization (hpf), respectively, during the embryonic/larval development. Compared with the 48 and 72 hpf exposure sets, the embryos/larvae in the 24 hpf exposure set showed much higher mortality rates which increased in a dose-dependent manner. Bradycardia and reduced blood flow were observed for the embryos/larvae treated with increasing concentrations of dextromethorphan. Morphological effects of dextromethorphan exposure, including yolk sac and cardiac edema, craniofacial malformation, lordosis, non-inflated swim bladder and missing gill, were also more frequent and severe among zebrafish embryos/larvae exposed to dextromethorphan at 24 hpf. Whether the more frequent and severe developmental toxicity of dextromethorphan observed among the embryos/larvae in the 24 hpf exposure set, as compared with the 48 and 72 hpf exposure sets, is due to the developmental expression of the phase I and phase II enzymes involved in the metabolism of dextromethorphan remains to be clarified. A reverse transcription-polymerase chain reaction analysis, nevertheless, revealed developmental stage-dependent expression of mRNAs encoding SULT3 ST1 and SULT3 ST3, two enzymes previously shown to be capable of sulfating dextrorphan, an active metabolite of dextromethorphan. Copyright © 2010 John Wiley & Sons, Ltd.

  4. Developmental Toxicity of Dextromethorphan in Zebrafish Embryos/Larvae

    PubMed Central

    Xu, Zheng; Williams, Frederick E.; Liu, Ming-Cheh

    2012-01-01

    Dextromethorphan is widely used in over-the-counter cough and cold medications. Its efficacy and safety for infants and young children remains to be clarified. The present study was designed to use the zebrafish as a model to investigate the potential toxicity of dextromethorphan during the embryonic and larval development. Three sets of zebrafish embryos/larvae were exposed to dextromethorphan at 24 hours post fertilization (hpf), 48 hpf, and 72 hpf, respectively, during the embryonic/larval development. Compared with the 48 and 72 hpf exposure sets, the embryos/larvae in the 24 hpf exposure set showed much higher mortality rates which increased in a dose-dependent manner. Bradycardia and reduced blood flow were observed for the embryos/larvae treated with increasing concentrations of dextromethorphan. Morphological effects of dextromethorphan exposure, including yolk sac and cardiac edema, craniofacial malformation, lordosis, non-inflated swim bladder, and missing gill, were also more frequent and severe among zebrafish embryos/larvae exposed to dextromethorphan at 24 hpf. Whether the more frequent and severe developmental toxicity of dextromethorphan observed among the embryos/larvae in the 24 hpf exposure set, as compared with the 48 and 72 hpf exposure sets, is due to the developmental expression of the Phase I and Phase II enzymes involved in the metabolism of dextromethorphan remains to be clarified. A reverse transcription-polymerase chain reaction (RT-PCR) analysis, nevertheless, revealed developmental stage-dependent expression of mRNAs encoding SULT3 ST1 and SULT3 ST3, two enzymes previously shown to be capable of sulfating dextrorphan, an active metabolite of dextromethorphan. PMID:20737414

  5. Dextromethorphan psychosis, dependence and physical withdrawal.

    PubMed

    Miller, Shannon C

    2005-12-01

    As part of a synthesis of evidence regarding the abuse and addiction liability of dextromethorphan (DM), an over-the-counter cough medicine available in over 140 preparations, an uncommonly published case of dextromethorphan dependence (addiction) is described, with specific, rarely published complications. The individual was interviewed and several medical databases were also reviewed (Medline, 1966-present; PubMed) for all content relating to the Keywords: dextromethorphan, abuse, dependence, cough medicine, addiction, withdrawal, psychosis. The patient evidenced history suggesting substance dependence, substance-induced psychosis and substance withdrawal in relation to DM. A literature review revealed that DM has specific serotonergic and sigma-1 opioidergic properties. Dextrorphan (DOR), the active metabolite of DM, has similar properties; however, DOR is a weaker sigma opioid receptor agonist, and a stronger NMDA receptor antagonist. DM and DOR display specific biological features of addiction, and are capable of inducing specific psychiatric sequelae. A specific, reproducible toxidrome with significant psychiatric effects occurred, when DM was abused at greater than indicated doses, with more profound and potentially life-threatening effects at even higher doses. DM withdrawal appears evident. DM's active metabolite, DOR, has pharmacodynamic properties and intoxication effects similar to dissociatives, and may be more responsible for the dissociative effect that this DM abuser sought. However, it is this same metabolite that may be fraught with the potentially life-threatening psychoses and dissociative-induced accidents, as well as addiction. While DM has been hypothesized as the most commonly abused dissociative, health-care providers seem largely unaware of its toxidrome and addiction liability.

  6. Combined dextromethorphan and chlorpheniramine intoxication in impaired drivers.

    PubMed

    Logan, Barry K

    2009-09-01

    Dextromethorphan is a nonprescription antitussive which has been gaining in popularity as an abused drug, because of the hallucinogenic, dissociative, and intoxicating effects it produces at high doses. This report describes a series of eight drivers arrested for driving under the influence of the combined effects of dextromethorphan and chlorpheniramine, and a further four drivers under the influence of dextromethorphan alone. In the combined dextromethorphan/chlorpheniramine cases, blood dextromethorphan concentrations ranged from 150 to 1220 ng/mL (n = 8; mean 676 ng/mL, median 670 ng/mL), and chlorpheniramine concentrations ranged from 70 to 270 ng/mL (n = 8; mean 200 ng/mL, median 180 ng/mL). The four cases without chlorpheniramine present had blood dextromethorphan concentrations between 190 and 1000 ng/mL (mean 570 ng/mL, median 545 ng/mL). Some drivers had therapeutic concentrations of other drugs present. Drivers generally displayed symptoms of central nervous system (CNS) depressant intoxication, and there was gross evidence of impairment in their driving, including weaving, leaving the lane of travel, failing to obey traffic signals, and involvement in collisions. Drug Recognition Expert opinions confirmed that the subjects were under the influence of a drug in the CNS-depressant category.

  7. Regulation of p-nitroanisole O-demethylation in perfused rat liver. Adenine nucleotide inhibition of NADP+-dependent dehydrogenases and NADPH-cytochrome c reductase.

    PubMed Central

    Kauffman, F C; Evans, R K; Reinke, L A; Thurman, R G

    1979-01-01

    Perfusion of rat livers with 10 mM-fructose or pretreatment of the rat with 6-aminonicotinamide (70 mg/kg) 6 h before perfusion decreased intracellular ATP concentrations and increased the rate of p-nitroanisole O-demethylation. This increase was accompanied by a decrease in the free [NADP+]/[NADPH] ratio calculated from concentrations of substrates assumed to be in near-equilibrium with isocitrate dehydrogenase. After pretreatment with 6-aminonicotinamide the [NADP+]/[NADPH] ratio also declined. Reduction of NADP+ during mixed-function oxidation may be explained by inhibition of of one or more NADPH-generating enzymes. Glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase and "malic" enzyme, partially purified from livers of phenobarbital-treated rats, were inhibited by ATP and ADP. Inhibitor constants of ATP for the four dehydrogenases varied considerably, ranging from 9 micrometer for "malic" enzyme to 1.85 mM for glucose 6-phosphate dehydrogenase. NADPH-cytochrome c reductase was also inhibited by ATP (Ki 2.8 mM) and by ADP (Ki 0.9 mM), but not by AMP. Concentrations of ATP and ADP that inhibited glucose 6-phosphate dehydrogenase and the reductase were comparable with concentrations in the intact liver. Thus agents that lower intracellular ATP may accelerate rates of mixed-function oxidation by a concerted mechanism involving deinhibition of NADPH-cytochrome c reductase and one or more NADPH-generating enzymes. PMID:44195

  8. Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illness

    DTIC Science & Technology

    2010-07-01

    09-2-0065 TITLE: Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illness PRINCIPAL INVESTIGATOR: William Joel Meggs, MD, PhD...From - To) 1 JUL 2009 - 30 JUN 2010 4. TITLE AND SUBTITLE Trial of Naltrexone and Dextromethorphan for Gulf War Veteravns’ Illness 5a... dextromethorphan & naltrexone for gulf war illness. 15. SUBJECT TERMS Dextromethorphan , naltexone, gulf war illness 16. SECURITY CLASSIFICATION OF

  9. Dextromethorphan Analogs: Receptor Binding and Pharmacological Profile of Novel Anticonvulsant/Neuroprotectant Drugs

    DTIC Science & Technology

    1993-05-13

    AD-POO8 801 Dextromethorphan Analogs: Receptor Binding and Pharmacological Profile of Novel Anticonvulsant/Neuroprotective Drugs F.C. Tortella, L...Baltimore, MD 21224 CD ABSTRACT A series of 3-substituted 17-methylmorphinan analogs of dextromethorphan (DM) have open developed which are...nTTrTTn) INTRODUCTION The antitussives dextromethorphan (DM), caramiphen and carbetapentane have distinguished themselves as anticonvulsant drugs (1

  10. [Pharmacokinetic study of a new chewing gum dextromethorphan delivery system].

    PubMed

    Liu, Juan; Tan, Qun-you; Liu, Bi-lin; Xu, Mei-ling; Zhao, Chun-jing; Zhang, Jing-qing

    2011-01-01

    To establish an high-performance liquid chromatography (HPLC)-based method for analysis of the pharmacokinetics and relative bioavailability of dextromethorphan chewing gum tablets in rabbits. The pharmacokinetic parameters and the relative bioavailability of dextromethorphan chewing gum preparation in rabbits were compared with those of the commercially available chewing dextromethorphan tablets using 3P97 software. Pharmacokinetic analysis of the new dextromethorphan chewing gum tablets showed a AUC of 488.76 ∓ 175.00 ng.ml(-1).h, C(max) of 95.45 ∓ 17.53 ng/ml, and t(max) of 1.83 ∓ 0.57 h as compared with the corresponding parameters of 370.13 ∓ 90.56 ng.ml(-1).h, 174.00 ∓ 47.88 ng.ml, and 1.04 ∓ 0.14 h for the commercially available chewing tablets. The relative bioavailability of the new chewing gum medicine system was (140.73 ∓ 65.91)%. The new dextromethorphan chewing gum preparation shows an increased AUC((0→)), decreased C(max), and prolonged t(max) in comparison with the commercially available chewing tablets, with also a greatly enhanced relative bioavailability.

  11. Dextromethorphan inhibition of voltage-gated proton currents in BV2 microglial cells.

    PubMed

    Song, Jin-Ho; Yeh, Jay Z

    2012-05-10

    Dextromethorphan, an antitussive drug, has a neuroprotective property as evidenced by its inhibition of microglial production of pro-inflammatory cytokines and reactive oxygen species. The microglial activation requires NADPH oxidase activity, which is sustained by voltage-gated proton channels in microglia as they dissipate an intracellular acid buildup. In the present study, we examined the effect of dextromethorphan on proton currents in microglial BV2 cells. Dextromethorphan reversibly inhibited proton currents with an IC(50) value of 51.7 μM at an intracellular/extracellular pH gradient of 5.5/7.3. Dextromethorphan did not change the reversal potential or the voltage dependence of the gating. Dextrorphan and 3-hydroxymorphinan, major metabolites of dextromethorphan, and dextromethorphan methiodide were ineffective in inhibiting proton currents. The results indicate that dextromethorphan inhibition of proton currents would suppress NADPH oxidase activity and, eventually, microglial activation. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. Acute renal failure after ingestion of guaifenesin and dextromethorphan.

    PubMed

    Small, Evan; Sandefur, Benjamin J

    2014-07-01

    Guaifenesin is a common nonprescription medication that has been implicated in drug-induced nephrolithiasis. Dextromethorphan, a nonprescription antitussive found in some guaifenesin-containing preparations, is increasingly recognized as a substance of abuse by many youth and young adults. Renally excreted medications known to have poor solubility in urine have the potential to precipitate when ingested in large quantity, leading to acute obstruction of the ureters and renal failure. We describe the case of a 22-year-old male who developed severe bilateral flank pain, hematuria, and oliguria after an isolated recreational ingestion of guaifenesin and dextromethorphan. The patient was found to have bilateral ureteral obstruction and acute renal failure, suspected to be secondary to precipitation of medication metabolites in the urine. This case highlights the potential for acute renal failure secondary to guaifenesin and dextromethorphan abuse. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Involvement of Sigma-1 Receptors in the Antidepressant-like Effects of Dextromethorphan

    PubMed Central

    Nguyen, Linda; Robson, Matthew J.; Healy, Jason R.; Scandinaro, Anna L.; Matsumoto, Rae R.

    2014-01-01

    Dextromethorphan is an antitussive with a high margin of safety that has been hypothesized to display rapid-acting antidepressant activity based on pharmacodynamic similarities to the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine. In addition to binding to NMDA receptors, dextromethorphan binds to sigma-1 (σ1) receptors, which are believed to be protein targets for a potential new class of antidepressant medications. The purpose of this study was to determine whether dextromethorphan elicits antidepressant-like effects and the involvement of σ1 receptors in mediating its antidepressant-like actions. The antidepressant-like effects of dextromethorphan were assessed in male, Swiss Webster mice using the forced swim test. Next, σ1 receptor antagonists (BD1063 and BD1047) were evaluated in conjunction with dextromethorphan to determine the involvement of σ receptors in its antidepressant-like effects. Quinidine, a cytochrome P450 (CYP) 2D6 inhibitor, was also evaluated in conjunction with dextromethorphan to increase the bioavailability of dextromethorphan and reduce exposure to additional metabolites. Finally, saturation binding assays were performed to assess the manner in which dextromethorphan interacts at the σ1 receptor. Our results revealed dextromethorphan displays antidepressant-like effects in the forced swim test that can be attenuated by pretreatment with σ1 receptor antagonists, with BD1063 causing a shift to the right in the dextromethorphan dose response curve. Concomitant administration of quinidine potentiated the antidepressant-like effects of dextromethorphan. Saturation binding assays revealed that a Ki concentration of dextromethorphan reduces both the Kd and the Bmax of [3H](+)-pentazocine binding to σ1 receptors. Taken together, these data suggest that dextromethorphan exerts some of its antidepressant actions through σ1 receptors. PMID:24587167

  14. Involvement of sigma-1 receptors in the antidepressant-like effects of dextromethorphan.

    PubMed

    Nguyen, Linda; Robson, Matthew J; Healy, Jason R; Scandinaro, Anna L; Matsumoto, Rae R

    2014-01-01

    Dextromethorphan is an antitussive with a high margin of safety that has been hypothesized to display rapid-acting antidepressant activity based on pharmacodynamic similarities to the N-methyl-D-aspartate (NMDA) receptor antagonist ketamine. In addition to binding to NMDA receptors, dextromethorphan binds to sigma-1 (σ1) receptors, which are believed to be protein targets for a potential new class of antidepressant medications. The purpose of this study was to determine whether dextromethorphan elicits antidepressant-like effects and the involvement of σ1 receptors in mediating its antidepressant-like actions. The antidepressant-like effects of dextromethorphan were assessed in male, Swiss Webster mice using the forced swim test. Next, σ1 receptor antagonists (BD1063 and BD1047) were evaluated in conjunction with dextromethorphan to determine the involvement of σ receptors in its antidepressant-like effects. Quinidine, a cytochrome P450 (CYP) 2D6 inhibitor, was also evaluated in conjunction with dextromethorphan to increase the bioavailability of dextromethorphan and reduce exposure to additional metabolites. Finally, saturation binding assays were performed to assess the manner in which dextromethorphan interacts at the σ1 receptor. Our results revealed dextromethorphan displays antidepressant-like effects in the forced swim test that can be attenuated by pretreatment with σ1 receptor antagonists, with BD1063 causing a shift to the right in the dextromethorphan dose response curve. Concomitant administration of quinidine potentiated the antidepressant-like effects of dextromethorphan. Saturation binding assays revealed that a Ki concentration of dextromethorphan reduces both the Kd and the Bmax of [(3)H](+)-pentazocine binding to σ1 receptors. Taken together, these data suggest that dextromethorphan exerts some of its antidepressant actions through σ1 receptors.

  15. Marmoset cytochrome P450 2D8 in livers and small intestines metabolizes typical human P450 2D6 substrates, metoprolol, bufuralol and dextromethorphan.

    PubMed

    Uehara, Shotaro; Uno, Yasuhiro; Hagihira, Yuya; Murayama, Norie; Shimizu, Makiko; Inoue, Takashi; Sasaki, Erika; Yamazaki, Hiroshi

    2015-01-01

    1. Although the New World non-human primate, the common marmoset (Callithrix jacchus), is a potentially useful animal model, comprehensive understanding of drug metabolizing enzymes is insufficient. 2. A cDNA encoding a novel cytochrome P450 (P450) 2D8 was identified in marmosets. The amino acid sequence deduced from P450 2D8 cDNA showed a high sequence identity (83-86%) with other primate P450 2Ds. Phylogenetic analysis showed that marmoset P450 2D8 was closely clustered with human P450 2D6, unlike P450 2Ds of miniature pig, dog, rabbit, guinea pig, mouse or rat. 3. Marmoset P450 2D8 mRNA was predominantly expressed in the liver and small intestine among the tissues types analyzed, whereas marmoset P450 2D6 mRNA was expressed predominantly in the liver where P450 2D protein was detected by immunoblotting. 4. By metabolic assays using marmoset P450 2D8 protein heterologously expressed in Escherichia coli, although P450 2D8 exhibits lower catalytic efficiency compared to marmoset and human P450 2D6 enzymes, P450 2D8 mediated O-demethylations of metoprolol and dextromethorphan and bufuralol 1'-hydroxylation. 5. These results suggest that marmoset P450 2D8 (also expressed in the extrahepatic tissues) has potential roles in drug metabolism in a similar manner to those of human and marmoset P450 2D6.

  16. Dextromethorphan abuse leading to assault, suicide, or homicide.

    PubMed

    Logan, Barry K; Yeakel, Jillian K; Goldfogel, Gary; Frost, Michael P; Sandstrom, Greg; Wickham, Dennis J

    2012-09-01

    Dextromethorphan is a commonly encountered antitussive medication which has found additional therapeutic use in the treatment of pseudobulbar disorder and as an adjunct to opiate use in pain management. Dextromethorphan at high doses has phencyclidine-like effects on the NMDA receptor system; recreational use of high doses has been found to cause mania and hallucinations. The toxicology and pharmacology of the drug in abuse are reviewed, and the historical literature of adverse psychiatric outcomes is assessed. Five new cases of dextromethorphan intoxication that resulted in assault, suicide, and homicide are reported, together with the corresponding toxicology results. Blood concentrations ranged from 300 to 19,000 μg/L. These results are compared with typical concentrations reported in therapeutic use and impaired driving cases. Based on these findings, dextromethorphan should be considered as a potential causative agent in subjects presenting with mania, psychosis, or hallucinations, and abusers are at risk for violent and self-destructive acts. © 2012 American Academy of Forensic Sciences.

  17. Dextromethorphan differentially affects opioid antinociception in rats

    PubMed Central

    Chen, Shiou-Lan; Huang, Eagle Yi-Kung; Chow, Lok-Hi; Tao, Pao-Luh

    2005-01-01

    Opioid drugs such as morphine and meperidine are widely used in clinical pain management, although they can cause some adverse effects. A number of studies indicate that N-methyl-D-aspartate (NMDA) receptors may play a role in the mechanism of morphine analgesia, tolerance and dependence. Being an antitussive with NMDA antagonist properties, dextromethorphan (DM) may have some therapeutic benefits when coadministered with morphine. In the present study, we investigated the effects of DM on the antinociceptive effects of different opioids. We also investigated the possible pharmacokinetic mechanisms involved. The antinociceptive effects of the μ-opioid receptor agonists morphine (5 mg kg−1, s.c.), meperidine (25 mg kg−1, s.c.) and codeine (25 mg kg−1, s.c.), and the κ-opioid agonists nalbuphine (8 mg kg−1, s.c.) and U-50,488H (20 mg kg−1, s.c.) were studied using the tail-flick test in male Sprague–Dawley rats. Coadministration of DM (20 mg kg−1, i.p.) with these opioids was also performed and investigated. The pharmacokinetic effects of DM on morphine and codeine were examined, and the free concentration of morphine or codeine in serum was determined by HPLC. It was found that DM potentiated the antinociceptive effects of some μ-opioid agonists but not codeine or κ-opioid agonists in rats. DM potentiated morphine's antinociceptive effect, and acutely increased the serum concentration of morphine. In contrast, DM attenuated the antinociceptive effect of codeine and decreased the serum concentration of its active metabolite (morphine). The pharmacokinetic interactions between DM and opioids may partially explain the differential effects of DM on the antinociception caused by opioids. PMID:15655510

  18. Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illness

    DTIC Science & Technology

    2013-07-01

    AD_________________ Award Number: W81XWH-09-2-0065 TITLE: Trial of Naltrexone and Dextromethorphan ...AND SUBTITLE 5a. CONTRACT NUMBER Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illness 5b. GRANT NUMBER W81XWH-09-2-0065 5c...Sciences has demonstrated that Morphine-related analogs, including Naltrexone and Dextromethorphan , have great potency in anti-inflammation and

  19. Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illness

    DTIC Science & Technology

    2012-07-01

    AD_________________ Award Number: W81XWH-09-2-0065 TITLE: Trial of Naltrexone and Dextromethorphan ...TITLE AND SUBTITLE 5a. CONTRACT NUMBER Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illness 5b. GRANT NUMBER W81XWH-09-2-0065...ABSTRACT Approval to separate the study into a separate dextromethorphan arm and naltrexone arm from the Department of Defense Institutional Review

  20. Autoradiographic Distribution and Applied Pharmacological Characteristics of Dextromethorphan and Related Antitissue/Anticonvulsant Drugs and Novel Analogs.

    DTIC Science & Technology

    1992-08-01

    OF DEXTROMETHORPHAN AND RELATED ANTITISSUE/ANTICONVULSANT DRUGS AND NOVEL ANALOGS PRINCIPAL INVESTIGATOR: Norman G. Bowery, Ph.D., DSc CONTRACTING...Characteristics of Dextromethorphan and DAMD17-90-C-0124 Related Anti ti ssue/ Anticonvul sant Drugs and Novel 6. AUTHOR(S) Analogs 61102A...13. ABSTRACT (Maximum 200 words) Binding of dextromethorphan and its analogues to the dextromethorphan binding site and to the PCP and glycine binding

  1. The Effect of Pre-Emptive Administration of Dextromethorphan on Postoperative Pain in Patients Undergoing Interval Laparoscopic Tubal Sterilization

    DTIC Science & Technology

    2001-10-01

    requirements following surgery. Dextromethorphan , a readily available nonopioid antitussive in clinical use for more than 40 years, is one such NMDA...receptor Anticosti. This prospective, randomized, double blind pilot study compared the effects over time when patients received dextromethorphan ...groups. Group I received 60 mg of dextromethorphan orally, and Group II received an oral placebo. Postoperative pain was assessed using an 11 point

  2. Autoradiographic Distribution and Applied Pharmacological Characteristics of Dextromethorphan and Related Antitissue/Anticonvulsant Drugs and Novel Analogs

    DTIC Science & Technology

    1993-10-01

    AD-A273 247 AD____ CONTRACT NO: DAMD17-90-C-0124 TITLE: AUTORADIOGRAPHIC DISTRIBUTION AND APPLIED PHARMACOLOGICAL CHARACTERISTICS OF DEXTROMETHORPHAN ...Anticonvulsants, Antitissue, Dextromethorphan , Autoradiography, Pharmacokinetics 16. PRICE CODE 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION...middle cerebral artery occlusion model with dextromethorphan , carbetapentane and three of the carbetapentane analogues, 11, B and D, which were

  3. Formulation and evaluation of dextromethorphan hydrobromide sustained release tablets.

    PubMed

    Meyyanathan, Subramania Nainar; Rajan, Sekar; Muralidaharan, Selvadurai; Siddaiah, Mahesh Kumar; Krishnaraj, Kaliaperumal; Suresh, Bhojraj

    2008-09-01

    Sustained release (SR) matrix tablets of dextromethorphan hydrobromide were prepared by wet granulation using hydroxypropyl methyl cellulose (HPMC-K-100 CR) as the hydrophilic rate controlling polymer. The effect of the concentration of the polymer and different fillers on the in vitro drug release rate was studied. The studies indicated that the drug release can be modulated by varying the concentration of the polymer and the fillers. A complete cross-over bioavailability study of the optimized formulation of the developed sustained tablets and marketed immediate release tablets was performed on six healthy male volunteers. The extent of absorption of drug from the SR tablets was significantly higher than that for the marketed dextromethorphan hydrobromide tablet because of lower elimination rate and longer half-life.

  4. Mechanism of action of dextromethorphan/quinidine:comparison with ketamine.

    PubMed

    Stahl, Stephen M

    2013-10-01

    Reports of rapid-onset but short-duration antidepressant effects in patients with treatment-resistant mood disorders after intravenous administration of ketamine have prompted efforts to find an agent with ketamine's properties that can be administered orally in repeated doses in order to sustain that action. One candidate for this dextromethorphan, and here the pharmacologic mechanism of action is compared and contrasted with that of ketamine.

  5. Efficacy of dextromethorphan and cyclosporine a for acute encephalopathy.

    PubMed

    Matsuo, Muneaki; Maeda, Toshiyuki; Ono, Nobuyasu; Sugihara, Susumu; Kobayashi, Ikuko; Koga, Daisuke; Hamasaki, Yuhei

    2013-03-01

    Acute encephalopathy with biphasic seizures and late reduced diffusion was recently established clinicoradiologically as an encephalopathy syndrome. The outcome of this encephalopathy is characterized by a low mortality rate and high incidence of neurologic sequelae. Although the exact pathogenesis of this encephalopathy is uncertain, excitotoxic injury with delayed neuronal death is proposed. On the basis of this hypothesis, we tried a combination therapy of N-methyl-D-aspartate receptor antagonist, dextromethorphan, and apoptosis inhibitor, cyclosporine A, in four patients with acute encephalopathy with biphasic seizures and late reduced diffusion. All patients recovered except for hyperactivity in one patient. Furthermore, an additional four patients with near-miss encephalopathy, who showed mild disturbance of consciousness at 24 hours after prolonged febrile seizures associated with exanthem subitum, recovered without secondary seizures by the early administration of dextromethorphan. The combination regimen of dextromethorphan and cyclosporine A could be effective for the treatment and prevention of acute encephalopathy with biphasic seizures and late reduced diffusion. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Pharmacology of dextromethorphan: Relevance to dextromethorphan/quinidine (Nuedexta®) clinical use.

    PubMed

    Taylor, Charles P; Traynelis, Stephen F; Siffert, Joao; Pope, Laura E; Matsumoto, Rae R

    2016-08-01

    Dextromethorphan (DM) has been used for more than 50years as an over-the-counter antitussive. Studies have revealed a complex pharmacology of DM with mechanisms beyond blockade of N-methyl-d-aspartate (NMDA) receptors and inhibition of glutamate excitotoxicity, likely contributing to its pharmacological activity and clinical potential. DM is rapidly metabolized to dextrorphan, which has hampered the exploration of DM therapy separate from its metabolites. Coadministration of DM with a low dose of quinidine inhibits DM metabolism, yields greater bioavailability and enables more specific testing of the therapeutic properties of DM apart from its metabolites. The development of the drug combination DM hydrobromide and quinidine sulfate (DM/Q), with subsequent approval by the US Food and Drug Administration for pseudobulbar affect, led to renewed interest in understanding DM pharmacology. This review summarizes the interactions of DM with brain receptors and transporters and also considers its metabolic and pharmacokinetic properties. To assess the potential clinical relevance of these interactions, we provide an analysis comparing DM activity from in vitro functional assays with the estimated free drug DM concentrations in the brain following oral DM/Q administration. The findings suggest that DM/Q likely inhibits serotonin and norepinephrine reuptake and also blocks NMDA receptors with rapid kinetics. Use of DM/Q may also antagonize nicotinic acetylcholine receptors, particularly those composed of α3β4 subunits, and cause agonist activity at sigma-1 receptors. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Patterns and Perceptions of Dextromethorphan Use in Adult Members of an Online Dextromethorphan Community.

    PubMed

    Pringle, George; McDonald, Michael P; Gabriel, Kara I

    2015-01-01

    Dextromethorphan (DXM) is a widely available antitussive that has, at elevated dose levels, euphoric and dissociative effects. This article presents the reported patterns and preferences of DXM use, and perceptions of DXM use among adult members of an online DXM community. Analyses were conducted of quantitative and qualitative responses from nine female and 43 male individuals, aged 18-63 years old. All respondents reported illegal and DXM drug use, beginning, on average, at 15.7 and 17.1 years of age, respectively. The majority of respondents first heard about DXM online or from a friend, preferred to use DXM alone, ingested substances concurrently with DXM to modify its effects, had not been to an emergency room or arrested because of their DXM use, and used DXM for its dissociative and mind-altering effects. DXM was perceived as safe and in no need of further regulation with only 14% of respondents mentioning DXM's addictive qualities. Findings from this sample of adult DXM users reveal a sophisticated subculture in which users report using DXM specifically to induce changes to their mental state and use a variety of substances to modify or enhance DXM's effects.

  8. Neuromodulatory effects of the dorsal hippocampal endocannabinoid system in dextromethorphan/morphine-induced amnesia.

    PubMed

    Ghasemzadeh, Zahra; Rezayof, Ameneh

    2017-01-05

    Dextromethorphan which is an active ingredient in many cough medicines has been previously shown to potentiate amnesic effect of morphine in rats. However, the effect of dextromethorphan, that is also a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, in combination with morphine on hippocampus-based long term memory has not been well characterized. The aim of the present study was to assess the possible role of endocannabinoid system of the dorsal hippocampus in dextromethorphan /morphine-induced amnesia. Our results showed that intraperitoneal (i.p.) injection of morphine (5mg/kg) or dextromethorphan (5-15mg/kg) before testing the passive avoidance learning induced amnesia. Combination of ineffective doses of dextromethorphan (7.5mg/kg, i.p.) and morphine (2mg/kg, i.p.) also produced amnesia, suggesting the enhancing effects of the drugs. To assess the effect of the activation or inhibition of the dorsal hippocampal cannabinoid CB1 receptors on this amnesia, ACPA or AM251 as selective receptor agonists or antagonists were respectively injected into the CA1 regions before systemic injection of dextromethorphan and morphine. Interestingly, intra-CA1 microinjection of ACPA (0.5-1ng/rat) improved the amnesic effect of dextromethorphan /morphine combination. The microinjection of AM251 into the CA1 region enhanced the response of the combination of dextromethorphan /morphine in inducing amnesia. Moreover, Intra-CA1 microinjection of AM251 inhibited the improving effect of ACPA on dextromethorphan /morphine-induced amnesia. It is important to note that intra-CA1 microinjection of the same doses of the agonist or antagonist by itself had no effects on memory formation. Thus, it can be concluded that the dorsal hippocampal endocannabinoid system, via CB1 receptor-dependent mechanism, may be involved in morphine/dextromethorphan -induced amnesia. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Differential Consequences of Tramadol in Overdosing: Dilemma of a Polymorphic Cytochrome P450 2D6-Mediated Substrate.

    PubMed

    Srinivas, Nuggehally R

    2015-09-01

    Tramadol is a centrally acting opioid analgesic that is prone to polymorphic metabolism via cytochrome P450 (CYP) 2D6. The generation of the active metabolite, O-desmethyltramadol, which occurs through the CYP 2D6 pathway, significantly contributes to the drug's activity. However, dosage adjustments of tramadol are typically not practiced in the clinic when treating patients who are homozygous extensive metabolizers, heterozygous extensive metabolizers, or poor metabolizers. In the event of a tramadol overdose, the consequences may be influenced importantly by the genotype or phenotype status of the subject. Depending on the individual subject's CYP 2D6 status, one may see excessive miotic-related toxicity driven by the excessive availability of O-desmethyltramadol or one may manifest mydriatic-related toxicity driven by the excessive availability of tramadol. This report provides pharmacokinetic perspectives in situations of tramadol overdosing.

  10. In silico and in vivo evaluation of flavonoid extracts on CYP2D6-mediated herb-drug interaction.

    PubMed

    Su, Zhe; Zhang, Bo; Zhu, Wenliang; Du, Zhimin

    2012-10-01

    Flavonoid extracts are widely used for preventing and treating ischemic heart disease. However, because many flavonoid extracts have been verified to inhibit CYP2D6 the main metabolic enzyme for the majority of antiarrhythmics and beta-blockers, co-administration of flavonoid extracts with these drugs may cause adverse herb-drug interaction in clinic. Here, we evaluated 43 common flavonoids on CYP2D6 inhibition in sillico and four commercial flavonoid extracts in vivo on the pharmacokinetics and pharmacodynamics of metoprolol in rats. Surprisingly, we found that the core skeletons of flavonoids instead of their substituents determine the extent of inhibiting CYP2D6 by a flavonoid extract. Isoflavones are less likely to inhibit CYP2D6, compared with other categories of flavonoids. Consistently, co-administration of soy extract that mainly contains isoflavones did not significantly increase plasma concentration of metoprolol and alter the systolic blood pressure of rats. Our results have implication in rationally selecting flavonoid extracts for therapeutic application.

  11. Review of dextromethorphan administration in 18 patients with subacute methotrexate central nervous system toxicity.

    PubMed

    Afshar, Maryam; Birnbaum, Daniel; Golden, Carla

    2014-06-01

    The pathogenesis of methotrexate central nervous system toxicity is multifactorial, but it is likely related to central nervous system folate homeostasis. The use of folinate rescue has been described to decrease toxicity in patients who had received intrathecal methotrexate. It has also been described in previous studies that there is an elevated level of homocysteine in plasma and cerebrospinal fluid of patients who had received intrathecal methotrexate. Homocysteine is an N-methyl-D-aspartate receptor agonist. The use of dextromethorphan, noncompetitive N-methyl-D-aspartate receptor receptor antagonist, has been used in the treatment of sudden onset of neurological dysfunction associated with methotrexate toxicity. It remains unclear whether the dextromethorphan impacted the speed of recovery, and its use remains controversial. This study reviews the use of dextromethorphan in the setting of subacute methotrexate central nervous system toxicity. Charts of 18 patients who had sudden onset of neurological impairments after receiving methotrexate and were treated with dextromethorphan were reviewed. The use of dextromethorphan in most of our patients resulted in symptomatic improvement. In this patient population, earlier administration of dextromethorphan resulted in faster improvement of impairments and led to prevention of recurrence of seizure activity induced by methotrexate central nervous system toxicity. Our study provides support for the use of dextromethorphan in patients with subacute methotrexate central nervous system toxicity. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Systemic dextromethorphan and dextrorphan are less toxic in rats than bupivacaine at equianesthetic doses.

    PubMed

    Chen, Yu-Wen; Wang, Jhi-Joung; Liu, Tzu-Ying; Chen, Yu-Chung; Hung, Ching-Hsia

    2011-01-01

    Dextrorphan, a major metabolite of dextromethorphan, produces the duration of spinal and cutaneous anesthesia similar to bupivacaine. The purpose of this study was to test the central nervous system and cardiovascular toxicity of bupivacaine, dextromethorphan, and dextrorphan. First, dose-response curves for dextromethorphan, dextrorphan, and bupivacaine (n = 8 at each testing point) were determined for cutaneous analgesia on the rat back, and equipotent doses were calculated. Next, during continuous intravenous infusion of equipotent doses of bupivacaine, dextromethorphan, and dextrorphan (n = 8 in each group), we observed the time to seizure, apnea, and complete cardiac arrest. A saline group (n = 7) was used for comparison. Mean arterial blood pressure (MAP), heart rate (HR), stroke volume (SV), and cardiac output (CO) were also monitored. Bupivacaine, dextromethorphan, and dextrorphan produced dose-dependent cutaneous anesthesia. A longer duration of equipotent infusion doses was required to produce seizures in the dextromethorphan group (10.6 ± 1.3 min) than in the bupivacaine group (7.6 ± 2.1 min) (P = 0.005). Dextrorphan did not produce any seizures. Compared with bupivacaine, time to apnea and complete cardiac arrest was longer with dextrorphan (P < 0.001) and with dextromethorphan (P = 0.001). Cardiovascular collapse, defined as a decline in MAP, HR, CO, and SV, was slower in the dextromethorphan and dextrorphan groups than in the bupivacaine group (P < 0.001 for both comparisons). At equipotent doses for local anesthesia, dextromethorphan and dextrorphan were less likely than bupivacaine to induce central nervous system and cardiovascular toxicity.

  13. Signs & Symptoms of Dextromethorphan Exposure from YouTube

    PubMed Central

    Chary, Michael; Park, Emily H.; McKenzie, Andrew; Sun, Julia; Manini, Alex F.; Genes, Nicholas

    2014-01-01

    Detailed data on the recreational use of drugs are difficult to obtain through traditional means, especially for substances like Dextromethorphan (DXM) which are available over-the-counter for medicinal purposes. In this study, we show that information provided by commenters on YouTube is useful for uncovering the toxicologic effects of DXM. Using methods of computational linguistics, we were able to recreate many of the clinically described signs and symptoms of DXM ingestion at various doses, using information extracted from YouTube comments. Our study shows how social networks can enhance our understanding of recreational drug effects. PMID:24533044

  14. Biodegradation of 2,4,6-TCA by the white-rot fungus Phlebia radiata is initiated by a phase I (O-demethylation)-phase II (O-conjugation) reactions system: implications for the chlorine cycle.

    PubMed

    Campoy, Sonia; Alvarez-Rodríguez, María Luisa; Recio, Eliseo; Rumbero, Angel; Coque, Juan-José R

    2009-01-01

    Thirteen species of white-rot fungi tested have been shown to efficiently biodegrade 1 mM 2,4,6-trichloroanisole (2,4,6-TCA) in liquid cultures. The maximum biodegradation rate (94.5% in 10-day incubations) was exhibited by a Phlebia radiata strain. The enzymes of the ligninolytic complex, laccase, lignin peroxidase (LiP), manganese peroxidase (MnP) and versatile peroxidase (VP) were not able to transform 2,4,6-TCA in in vitro reactions, indicating that the ligninolytic complex was not involved in the initial attack to 2,4,6-TCA. Instead, the first biodegradative steps were carried out by a phase I and phase II reactions system. Phase I reaction consisted on a O-demethylation catalysed by a microsomal cytochrome P-450 monooxygenase to produce 2,4,6-trichlorophenol (2,4,6-TCP). Later, in a phase II reaction catalysed by a microsomal UDP-glucosyltransferase, 2,4,6-TCP was detoxified by O-conjugation with D-glucose to produce 2,4,6-TCP-1-O-d-glucoside (TCPG). This compound accumulated in culture supernatants, reaching its maximum concentration between 48 and 72 h of growth. TCPG levels decreased constantly by the end of fermentation, indicating that it was subsequently metabolized. A catalase activity was able to break in vitro the glycosidic link to produce 2,4,6-TCP, whereas ligninolytic enzymes did not have a significant effect on the biotransformation of that compound. Once formed, 2,4,6-TCP was further degraded as detected by a concomitant release of 2.6 mol of chloride ions by 1 mol of initial 2,4,6-TCA, indicating that this compound underwent almost a complete dehalogenation and biodegradation. It was concluded that P. radiata combines two different degradative mechanisms in order to biodegrade 2,4,6-TCA. The significance of the capability of white-rot fungi to O-demethylate chloroanisoles for the global chlorine cycle is discussed.

  15. Dextromethorphan/quinidine for the treatment of pseudobulbar affect.

    PubMed

    Patatanian, Edna; Casselman, Jessica

    2014-04-01

    To evaluate the role of dextromethorphan/quinidine (DM/Q; Nuedexta™) in the treatment of pseudobulbar affect (PBA). A literature search of MEDLINE/PubMed (January 1966-June 2013) was conducted using search terms pseudobulbar affect, pathological laughing and/or crying, emotional lability, dextromethorphan, and quinidine. English language clinical trials and case reports evaluating the safety and efficacy of DM/Q in PBA were included for review. Bibliographies of all relevant articles were reviewed for additional citations. PBA, a poorly understood disorder, is characterized by involuntary crying and/or laughing. In the past, antidepressants and antiepileptics have been used off-label with mixed results. Four clinical trials have evaluated the use of DM/Q for the treatment of PBA. Although the therapeutic outcomes with DM/Q have been positive, interpretation of the published evidence is limited by small sample size and short treatment duration. Based on the data available, DM/Q may be a viable, short-term treatment alternative for PBA. Long-term safety and efficacy data are lacking.

  16. Nonaqueous capillary electrophoresis of dextromethorphan and its metabolites.

    PubMed

    Pelcová, Marta; Langmajerová, Monika; Cvingráfová, Eliška; Juřica, Jan; Glatz, Zdeněk

    2014-10-01

    This study deals with the nonaqueous capillary electrophoretic separation of dextromethorphan and its metabolites using a methanolic background electrolyte. The optimization of separation conditions was performed in terms of the resolution of dextromethorphan and dextrorphan and the effect of separation temperature, voltage, and the characteristics of the background electrolyte were studied. Complete separation of all analytes was achieved in 40 mM ammonium acetate dissolved in methanol. Hydrodynamic injection was performed at 3 kPa for 4 s. The separation voltage was 20 kV accompanied by a low electric current. The ultraviolet detection was performed at 214 nm, the temperature of the capillary was 25°C. These conditions enabled the separation of four analytes plus the internal standard within 9 min. Further, the developed method was validated in terms of linearity, sensitivity, and repeatability. Rat liver perfusate samples were subjected to the nonaqueous capillary electrophoretic method to illustrate its applicability. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Dextromethorphan interactions with histaminergic and serotonergic treatments to reduce nicotine self-administration in rats.

    PubMed

    Briggs, Scott A; Hall, Brandon J; Wells, Corinne; Slade, Susan; Jaskowski, Paul; Morrison, Margaret; Rezvani, Amir H; Rose, Jed E; Levin, Edward D

    2016-03-01

    Combining effective treatments with diverse mechanisms of action for smoking cessation may provide better therapy by targeting multiple points of control in the neural circuits underlying addiction. Previous research in a rat model has shown that dextromethorphan, which has α3β4 nicotinic and NMDA glutamatergic antagonist actions, significantly decreases nicotine self-administration. We have found in the rat model that the H1 histamine antagonist pyrilamine and the serotonin 5HT2C agonist lorcaserin also significantly reduce nicotine self-administration. The current studies were conducted to determine the interactive effects of dextromethorphan with pyrilamine and lorcaserin on nicotine self-administration in rats. Young adult female rats were fitted with jugular IV catheters and trained to self-administer a nicotine infusion dose of 0.03-mg/kg/infusion. In an initial dose-effect function study of dextromethorphan, we found a monotonic decrease in nicotine self-administration over a dose range of 1 to 30-mg/kg with the lowest effective dose of 3-mg/kg. Then, with two separate cohorts of rats, dextromethorphan (0, 3.3, and 10-mg/kg) interactions with pyrilamine (0, 4.43, and 13.3-mg/kg) were investigated as well as interactions with lorcaserin (0, 0.3125 and 0.625-mg/kg). In the pyrilamine-dextromethorphan interaction study, an acute dose of pyrilamine (13.3-mg/kg) as well as an acute dose of dextromethorphan caused a significant decrease in nicotine self-administration. There were mutually augmenting effects of these two drugs. The combination of dextromethorphan (10-mg/kg) and pyrilamine (13.3-mg/kg) significantly lowered nicotine self-administration relative to either 10-mg/kg of dextromethorphan alone (p<0.05) or 13.3-mg/kg of pyrilamine alone (p<0.0005). In the lorcaserin-dextromethorphan study, an acute dose of lorcaserin (0.312-mg/kg) as well as an acute dose of dextromethorphan (10-mg/kg) caused a significant decrease in nicotine self

  18. Dextromethorphan Interactions with Histaminergic and Serotonergic Treatments to Reduce Nicotine Self-administration in Rats

    PubMed Central

    Briggs, Scott A.; Hall, Brandon J.; Wells, Corinne; Slade, Susan; Jaskowski, Paul; Morrison, Margaret; Rezvani, Amir H.; Rose, Jed E.; Levin, Edward D.

    2015-01-01

    Combining effective treatments with diverse mechanisms of action for smoking cessation may provide better therapy by targeting multiple points of control in the neural circuits underlying addiction. Previous research in a rat model has shown that dextromethorphan, which has α3β4 nicotinic and NMDA glutamatergic antagonist actions, significantly decreases nicotine self-administration. We have found in the rat model that the H1 histamine antagonist pyrilamine and the serotonin 5HT2c agonist lorcaserin also significantly reduce nicotine self-administration. The current studies were conducted to determine the interactive effects of dextromethorphan with pyrilamine and lorcaserin on nicotine self-administration in rats. Young adult female rats were fitted with jugular IV catheters and trained to self-administer a nicotine infusion dose of 0.03-mg/kg/infusion. In an initial dose-effect function study of dextromethorphan, we found a monotonic decrease in nicotine self-administration over a dose range of 1 to 30-mg/kg with a lowest effective dose of 3-mg/kg. Then, with two separate cohorts of rats, dextromethorphan (0, 3.3, and 10-mg/kg) interactions with pyrilamine (0, 4.43, and 13.3-mg/kg) were investigated as well as interactions with lorcaserin (0, 0.3125 and 0.625-mg/kg). In the pyrilamine-dextromethorphan interaction study, the acute dose of pyrilamine (13.3-mg/kg) as well as an acute dose of dextromethorphan caused a significant decrease in nicotine self-administration. There were mutually augmenting effects of these two drugs. The combination of dextromethorphan (10-mg/kg) and pyrilamine (13.3-mg/kg) significantly lowered nicotine self-administration relative to either 10-mg/kg of dextromethorphan alone (p<0.05) or 13.3-mg/kg of pyrilamine alone (p<0.0005). In the lorcaserin-dextromethorphan study, an acute dose of lorcaserin (0.312-mg/kg) as well as an acute dose of dextromethorphan (10-mg/kg) caused a significant decrease in nicotine self

  19. Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illnesses

    DTIC Science & Technology

    2014-07-01

    low dose naltrexone have established benefits in syndromes related to Gulf War Illness such as fibromyalgia. We have successfully enrolled 41 subjects...09-2-0065 TITLE: Trial of Naltrexone and Dextromethorphan for Gulf War Veterans Illnesses PRINCIPAL INVESTIGATOR: William J. Meggs, MD, PhD...Dextromethorphan and Naltrexone for Gulf War Veterens’ Illness 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-09-2-0065 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR

  20. Dextromethorphan, chlorphenamine and serotonin toxicity: case report and systematic literature review.

    PubMed

    Monte, Andrew A; Chuang, Ryan; Bodmer, Michael

    2010-12-01

    The aim of this review was to describe a patient with serotonin toxicity after an overdose of dextromethorphan and chlorphenamine and to perform a systematic literature review exploring whether dextromethorphan and chlorphenamine may be equally contributory in the development of serotonin toxicity in overdose. A Medline literature review was undertaken to identify cases of serotonin toxicity due to dextromethorphan and/or chlorphenamine. Case reports were included if they included information on the ingested dose or plasma concentrations of dextromethorphan and/or chlorphenamine, information about co-ingestions and detailed clinical information to evaluate for serotonin toxicity. Cases were reviewed by two toxicologists and serotonin toxicity, defined by the Hunter criteria, was diagnosed when appropriate. The literature was then reviewed to evaluate whether chlorphenamine may be a serotonergic agent. One hundred and fifty-five articles of dextromethorphan or chlorphenamine poisoning were identified. There were 23 case reports of dextromethorphan, of which 18 were excluded for lack of serotonin toxicity. No cases were identified in which serotonin toxicity could be solely attributed to chlorphenamine. This left six cases of dextrometorphane and/or chlorphenamine overdose, including our own, in which serotonin toxicity could be diagnosed based on the presented clinical information. In three of the six eligible cases dextromethorphan and chlorphenamine were the only overdosed drugs. There is substantial evidence from the literature that chlorphenamine is a similarly potent serotonin re-uptake inhibitor when compared with dextrometorphan. Chlorphenamine is a serotonergic medication and combinations of chlorphenamine and dextromethorphan may be dangerous in overdose due to an increased risk of serotonin toxicity. © 2010 The Authors. British Journal of Clinical Pharmacology © 2010 The British Pharmacological Society.

  1. Dextromethorphan, chlorphenamine and serotonin toxicity: case report and systematic literature review

    PubMed Central

    Monte, Andrew A; Chuang, Ryan; Bodmer, Michael

    2010-01-01

    The aim of this review was to describe a patient with serotonin toxicity after an overdose of dextromethorphan and chlorphenamine and to perform a systematic literature review exploring whether dextromethorphan and chlorphenamine may be equally contributory in the development of serotonin toxicity in overdose. A Medline literature review was undertaken to identify cases of serotonin toxicity due to dextromethorphan and/or chlorphenamine. Case reports were included if they included information on the ingested dose or plasma concentrations of dextromethorphan and/or chlorphenamine, information about co-ingestions and detailed clinical information to evaluate for serotonin toxicity. Cases were reviewed by two toxicologists and serotonin toxicity, defined by the Hunter criteria, was diagnosed when appropriate. The literature was then reviewed to evaluate whether chlorphenamine may be a serotonergic agent. One hundred and fifty-five articles of dextromethorphan or chlorphenamine poisoning were identified. There were 23 case reports of dextromethorphan, of which 18 were excluded for lack of serotonin toxicity. No cases were identified in which serotonin toxicity could be solely attributed to chlorphenamine. This left six cases of dextrometorphane and/or chlorphenamine overdose, including our own, in which serotonin toxicity could be diagnosed based on the presented clinical information. In three of the six eligible cases dextromethorphan and chlorphenamine were the only overdosed drugs. There is substantial evidence from the literature that chlorphenamine is a similarly potent serotonin re-uptake inhibitor when compared with dextrometorphan. Chlorphenamine is a serotonergic medication and combinations of chlorphenamine and dextromethorphan may be dangerous in overdose due to an increased risk of serotonin toxicity. PMID:21175434

  2. Dextromethorphan/quinidine: a review of its use in adults with pseudobulbar affect.

    PubMed

    Yang, Lily P H; Deeks, Emma D

    2015-01-01

    Fixed-dose dextromethorphan/quinidine capsules (Nuedexta(®)) utilize quinidine to inhibit the metabolism of dextromethorphan, enabling high plasma dextromethorphan concentrations to be reached without using a larger dose of the drug. The drug combination is the first treatment to be approved for pseudobulbar affect (PBA), a condition of contextually inappropriate/exaggerated emotional expression that often occurs in adults with neurological damage conditions, such as amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), stroke, traumatic brain injury, Alzheimer's disease or Parkinson's disease. Dextromethorphan/quinidine at the recommended dosages of 20/10 or 30/10 mg twice daily reduced the rate of PBA episodes and improved PBA severity in a 12-week, double-blind, placebo-controlled trial in adults with ALS or MS (STAR), with further improvements in the severity of the condition observed in a 12-week open-label extension phase. Dextromethorphan/quinidine 20/10 mg twice daily also improved PBA secondary to dementia in a cohort of a 12-week noncomparative trial (PRISM II). The drug combination was generally well tolerated in these studies, with no particular safety or tolerability concerns. Although longer-term efficacy and tolerability data for dextromethorphan/quinidine 20/10 or 30/10 mg twice daily would be beneficial, current evidence indicates that it is a useful option in the treatment of adults with PBA.

  3. Efficacy and tolerability of levodropropizine in adult patients with non-productive cough. Comparison with dextromethorphan.

    PubMed

    Catena, E; Daffonchio, L

    1997-01-01

    The results of a double-blind, randomized clinical trial involving 209 adult patients of either sex with moderate non-productive cough are reported. The therapeutic efficacy and the tolerability of levodropropizine syrup (60 mg t.i.d. for 5 days) was evaluated in comparison with dextromethorphan syrup (15 mg t.i.d. for 5 days). Efficacy was assessed by the number of coughing spells in a 6h period, the cough frequency classes, the cough intensity and the night awakenings due to cough. Tolerability was evaluated by laboratory results, vital signs and any adverse event occurred during the clinical trial, including presence or absence of somnolence. Independently from the underlying pathology and from the degree of baseline cough severity, the number of coughing spells was significantly (P < 0.05) reduced by both levodropropizine and dextromethorphan already after the 2nd day of treatment, the effect and its time of onset being similar for both drugs. Cough intensity was significantly (P < 0.01) reduced by both drugs throughout the treatment, at an earlier time with levodropropizine than with dextromethorphan. Concurrently with the relief of cough, the number of night awakenings was decreased remarkably and significantly (P < 0.05), with levodropropizine displaying an improvement significantly higher (P < 0.05) than dextromethorphan. No change in laboratory tests values was considered clinically relevant and vital signs were not clinically affected by the study drugs. The number of patients reporting adverse events was significantly higher (P < 0.05) in the dextromethorphan (12.1%) than in the levodropropizine (3.6%) group. Overall, somnolence was reported for a low percentage of patients with both drugs, with the percentage of patients experiencing this side effect being one half in the group treated with levodropropizine (4.6%) as compared with dextromethorphan (10.4%). These results confirm the antitussive effectiveness of levodropropizine and point out a more

  4. Preoperative dextromethorphan reduces intraoperative but not postoperative morphine requirements after laparotomy.

    PubMed

    Grace, R F; Power, I; Umedaly, H; Zammit, A; Mersiades, M; Cousins, M J; Mather, L E

    1998-11-01

    N-methyl-D-aspartate (NMDA) antagonists combined with opioids are thought to be effective in the control of pain states. We evaluated morphine use and analgesia in 37 patients postlaparotomy. Patients received 60 mg of oral dextromethorphan or placebo the night before and again 1 h before surgery. Morphine was titrated intraoperatively to maintain blood pressure and heart rate within 20% of baseline and postoperatively via patient-controlled analgesia (PCA). The dextromethorphan and placebo groups were compared for morphine use intraoperatively, in recovery, via PCA in the first 4 and 24 h, and total use over the study period. Pain scores at rest and on activity for the first 4 and 24 h were also compared. Intraoperatively, the dextromethorphan group required less morphine: 13.1+/-4.3 vs 17.6+/-6.0 mg (P = 0.012). Postoperatively, there was no significant difference between the dextromethorphan and placebo groups for morphine use: in the recovery room 10.9+/-7.7 vs 12.1+/-7.7 mg; the first 4 h of PCA 15.9+/-9.3 vs 12.7+/-5.1 mg; the first 24 h of PCA 76.4+/-44.7 vs 61.8+/-27.5 mg; or in total morphine use 100.4+/-49.5 vs 91.5+/-3.1 mg. Pain scores for the two groups were not statistically different throughout the study period. We conclude that 60 mg of oral dextromethorphan given the night before and repeated an hour before surgery does not provide a postoperative morphine-sparing effect or improve analgesia after laparotomy. Patients given dextromethorphan before surgery had significantly reduced intraoperative morphine requirements. However, postoperative morphine requirements were unaltered. Dextromethorphan may need to be continued postoperatively to improve postoperative analgesia.

  5. Dextromethorphan as a phenotyping test to predict endoxifen exposure in patients on tamoxifen treatment.

    PubMed

    de Graan, Anne-Joy M; Teunissen, Sebastiaan F; de Vos, Filip Y F L; Loos, Walter J; van Schaik, Ron H N; de Jongh, Felix E; de Vos, Aad I; van Alphen, Robbert J; van der Holt, Bronno; Verweij, Jaap; Seynaeve, Caroline; Beijnen, Jos H; Mathijssen, Ron H J

    2011-08-20

    Tamoxifen, a widely used agent for the prevention and treatment of breast cancer, is mainly metabolized by CYP2D6 and CYP3A to form its most abundant active metabolite, endoxifen. Interpatient variability in toxicity and efficacy of tamoxifen is substantial. Contradictory results on the value of CYP2D6 genotyping to reduce the variable efficacy have been reported. In this pharmacokinetic study, we investigated the value of dextromethorphan, a known probe drug for both CYP2D6 and CYP3A enzymatic activity, as a potential phenotyping probe for tamoxifen pharmacokinetics. In this prospective study, 40 women using tamoxifen for invasive breast cancer received a single dose of dextromethorphan 2 hours after tamoxifen intake. Dextromethorphan, tamoxifen, and their respective metabolites were quantified. Exposure parameters of all compounds were estimated, log transformed, and subsequently correlated. A strong and highly significant correlation (r = -0.72; P < .001) was found between the exposures of dextromethorphan (0 to 6 hours) and endoxifen (0 to 24 hours). Also, the area under the plasma concentration-time curve of dextromethorphan (0 to 6 hours) and daily trough endoxifen concentration was strongly correlated (r = -0.70; P < .001). In a single patient using the potent CYP2D6 inhibitor paroxetine, the low endoxifen concentration was accurately predicted by dextromethorphan exposure. Dextromethorphan exposure after a single administration adequately predicted endoxifen exposure in individual patients with breast cancer taking tamoxifen. This test could contribute to the personalization and optimization of tamoxifen treatment, but it needs additional validation and simplification before being applicable in future dosing strategies.

  6. Autoradiographic Distribution and Applied Pharmacological Characteristics of Dextromethorphan and Related Antitissue/Anticonvulsant Drugs and Novel Analogs

    DTIC Science & Technology

    1991-11-01

    dextromethorphan, and its receptor, in normal and abnormal brain. Dextromethorphan is a non-opioid cough suppressant. It is as potent as codeine, but has the...at least one pharmacological effect in common with certain opioids in itc antitussive action and naloxone has been Shown to posAC3s neuroprotective

  7. Autoradiographic Distribution and Applied Pharmacological Characteristics of Dextromethorphan and Related Antitissue/Anticonvulsant Drugs and Novel Analogs.

    DTIC Science & Technology

    1994-10-01

    Maximum 200 words) Dextromethorphan is an antitussive compound with anticonvulsant and neuroprotective propertie arising from actions within the...BRAIN Introduction Dextromethorphan (DM) is a non-opioid cough suppressant which is the dextrorotatory isomer of the opioid levorphanol. However, it

  8. Dextromethorphan abuse in Thai adolescents: A report of two cases and review of literature.

    PubMed

    Manaboriboon, Boonying; Chomchai, Chulathida

    2005-11-01

    Dextromethorphan is an opiod-derived, easily available cough remedy that, when used in large quantities, can have stimulatory effects which mimic that of amphetamine and other psychedelic drugs. Due to its easy availability, dextromethorphan is gaining widespread popularity as a recreational drug among Thai youths. Symptoms of overdose are directly related to its pharmacodynamic and pharmacokinetic properties. Dextromethorphan is metabolized by cytochrome p450 2D6, an isoenzyme that exhibit polymorphism in Asians. The drug is also a serotonin-reuptake inhibitor and has significant interactions with other drugs that exert their effects through the serotonin pathway such as the amphetamines, cocaine, and Lysergic Acid (LSD). We report here two cases of dextromethorphan overdose that presented to the Pediatric Toxicology Service at Siriraj Hospital, Bangkok, Thailand. Both cases presented with hyper-agitation, confusion, with signs of sympathomimetic overdose. Both patients were treated with supportive care and fully recovered within 24 hours without sequalae. Although the acute toxicity of dextromethorphan is abated within 24 hours, its pharmacological properties still render it a dangerous drug to use alone or in combination with other drugs.

  9. Dextromethorphan mediated bitter taste receptor activation in the pulmonary circuit causes vasoconstriction.

    PubMed

    Upadhyaya, Jasbir D; Singh, Nisha; Sikarwar, Anurag S; Chakraborty, Raja; Pydi, Sai P; Bhullar, Rajinder P; Dakshinamurti, Shyamala; Chelikani, Prashen

    2014-01-01

    Activation of bitter taste receptors (T2Rs) in human airway smooth muscle cells leads to muscle relaxation and bronchodilation. This finding led to our hypothesis that T2Rs are expressed in human pulmonary artery smooth muscle cells and might be involved in regulating the vascular tone. RT-PCR was performed to reveal the expression of T2Rs in human pulmonary artery smooth muscle cells. Of the 25 T2Rs, 21 were expressed in these cells. Functional characterization was done by calcium imaging after stimulating the cells with different bitter agonists. Increased calcium responses were observed with most of the agonists, the largest increase seen for dextromethorphan. Previously in site-directed mutational studies, we have characterized the response of T2R1 to dextromethorphan, therefore, T2R1 was selected for further analysis in this study. Knockdown with T2R1 specific shRNA decreased mRNA levels, protein levels and dextromethorphan-induced calcium responses in pulmonary artery smooth muscle cells by up to 50%. To analyze if T2Rs are involved in regulating the pulmonary vascular tone, ex vivo studies using pulmonary arterial and airway rings were pursued. Myographic studies using porcine pulmonary arterial and airway rings showed that stimulation with dextromethorphan led to contraction of the pulmonary arterial and relaxation of the airway rings. This study shows that dextromethorphan, acting through T2R1, causes vasoconstrictor responses in the pulmonary circuit and relaxation in the airways.

  10. Dextromethorphan attenuated inflammation and combined opioid use in humans undergoing methadone maintenance treatment.

    PubMed

    Chen, Shiou-Lan; Lee, Sheng-Yu; Tao, Pao-Luh; Chang, Yun-Hsuan; Chen, Shih-Heng; Chu, Chun-Hsien; Chen, Po See; Lee, I Hui; Yeh, Tzung Lieh; Yang, Yen Kuang; Hong, Jau-Shyong; Lu, Ru-Band

    2012-12-01

    Recent studies show that proinflammatory cytokines might be related to the development of opioid dependence (physiological, psychological, or both). In a double-blind, randomly stratified clinical trial investigating whether add-on dextromethorphan (60-120 mg/day) attenuated inflammation and the combined use of opioids in heroin-dependent patients undergoing methadone maintenance treatment, we evaluated whether inflammation is related to the progression of opioid dependence. All participants (107 heroin-dependent patients and 84 nondependent healthy controls) were recruited from National Cheng Kung University Hospital. Their plasma cytokine levels were measured to evaluate the effect of add-on dextromethorphan. Plasma TNF-α and IL-8 levels were significantly higher in long-term heroin-dependent patients than in healthy controls (p < 0.001). Chronic heroin-use-induced TNF-α and IL-8 levels were significantly (p < 0.05) attenuated in patients treated for 12 weeks with add-on dextromethorphan. Moreover, both tolerance to methadone and the combined use of opioids were significantly (p < 0.05) attenuated in patients taking dextromethorphan. We conclude that dextromethorphan might be a feasible adjuvant therapeutic for attenuating inflammation and inhibiting methadone tolerance and combined opioid use in heroin-dependent patients.

  11. Analgesic effects of dextromethorphan and morphine in patients with chronic pain.

    PubMed

    Heiskanen, Tarja; Härtel, Brita; Dahl, Marja-Liisa; Seppälä, Timo; Kalso, Eija

    2002-04-01

    N-methyl-aspartate (NMDA) receptor antagonists have been shown to improve opioid analgesia in the animal model. The cough suppressant dextromethorphan is a clinically available NMDA-receptor antagonist. In this randomised, double-blind, placebo-controlled study 20 patients with chronic pain of several years duration were given 100 mg of oral dextromethorphan or matching placebo 4 h prior to an intravenous infusion of morphine 15 mg. Pain intensity and adverse effects were assessed at 0, 4, 5 and 7 h. Dextromethorphan had no effect on morphine analgesia: the mean (+/-SEM) visual analogue scores for pain relief (VAS, 0-100 mm) at the end of the morphine infusion were 38 (+/-6) for dextromethorphan+morphine and 38 (+/-7) for placebo+morphine. VAS scores for pain intensity were comparable both at rest and at movement at all time points. The most common adverse effects reported were dizziness, nausea and sedation. There were no significant differences in either the incidence or severity of adverse effects. In conclusion, oral dextromethorphan 100 mg had no effect on pain relief by intravenous morphine 15 mg in patients with chronic pain.

  12. Decreased cocaine- and lidocaine-induced seizure response by dextromethorphan and DNQX in rat.

    PubMed

    Barat, S A; Abdel-Rahman, M S

    1997-05-09

    The present study investigated the effect of dextromethorphan and 6,7-dinitroquinoxaline-2,3-dione (DNQX) pre-treatment on the development of cocaine- and lidocaine-induced seizures. The dopaminergic action of cocaine was also studied. The NMDA antagonist dextromethorphan and the non-NMDA (AMPA/kainate) antagonist DNQX both significantly decreased the intensity of the seizure response to intravenous convulsant doses of cocaine and lidocaine individually (20 mg/kg) and in combination (5 mg/kg each). The incidence of seizures in rats receiving cocaine or lidocaine individually was significantly reduced by pre-treatment with dextromethorphan but not DNQX. Haloperidol did not have an effect on the incidence or intensity of seizures induced by cocaine or lidocaine, alone or in combination. The results suggest that local anesthetic-induced convulsive seizures are mediated by excitatory glutamate transmission through both NMDA and non-NMDA receptor systems.

  13. The effect of grape seed extract on the pharmacokinetics of dextromethorphan in healthy volunteers.

    PubMed

    Goey, Andrew K L; Meijerman, Irma; Beijnen, Jos H; Schellens, Jan H M

    2013-11-01

    Grape seed extract (GSE) has been shown to inhibit the cytochrome P450 (CYP) 2D6 isoenzyme in vitro. To determine the clinical effect of GSE on CYP2D6, the pharmacokinetic interaction between GSE and the sensitive CYP2D6 probe dextromethorphan in healthy adult volunteers was examined. In this open label, randomized, cross-over study, 30 subjects were assigned to cohort A or B. Both cohorts ingested 30 mg dextromethorphan hydrobromide on day 1 and day 10. Cohort A received 100 mg GSE capsules three times daily on days 8, 9 and 10, while cohort B started with GSE on day -1 until day 1. After urine collection (0-8 h) on day 1 and day 10, the urinary dextromethorphan to dextrorphan metabolic ratio was determined. Among 28 evaluable subjects, an increase of the urinary metabolic ratio was observed in 16 subjects (57 %). The mean metabolic ratio (± standard deviation) before and after GSE supplementation was 0.41 (± 0.56) and 0.48 (± 0.59), respectively. This result was neither statistically (P = 0.342) nor clinically [geometric mean ratio 1.10, 90 % CI (0.93-1.30)] significant. Further, the majority (73 %) of the included subjects did not experience any adverse events after intake of dextromethorphan or GSE. Supplementation of GSE did not significantly affect the urinary dextromethorphan to dextrorphan metabolic ratio in healthy volunteers. The results of this clinical study indicate that GSE appears to be safe to combine with drugs extensively metabolized by CYP2D6, such as dextromethorphan and tamoxifen.

  14. Perioperative Dextromethorphan as an Adjunct for Postoperative Pain: a Meta-Analysis of Randomized Controlled Trials

    PubMed Central

    King, Michael R.; Ladha, Karim S.; Gelineau, Amanda M.; Anderson, T. Anthony

    2015-01-01

    Background N-methyl-D-aspartate (NMDA) receptor antagonists have been shown to reduce perioperative pain and opioid use. We performed a meta-analysis to determine whether the use of perioperative dextromethorphan lowers opioid consumption or pain scores. Methods PubMed, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, pubget, and Embase were searched. Studies were included if they were randomized, double-blinded, placebo controlled trials written in English, performed on patients ≥12 years. For comparison of opioid use, included studies tracked total consumption of intravenous or intramuscular opioids over 24 to 48 hours. Pain score comparisons were performed at 1 hour, 4 to 6 hours, and 24 hours postoperatively. Difference in means (MD) was used for effect size. Results Forty studies were identified and 21 were eligible for one or more comparisons. In 848 patients from 14 trials, opioid consumption favored dextromethorphan (MD -10.51 mg intravenous morphine equivalents; 95% confidence interval [CI]: -16.48 mg to -4.53 mg; p = 0.0006). In 884 patients from 13 trials, pain at 1 hour favored dextromethorphan (MD -1.60; 95% CI: -1.89 to -1.31; p < 0.00001). In 950 patients from 13 trials, pain at 4-6 hours favored dextromethorphan (MD -0.89; 95% CI: -1.11 to -0.66; p < 0.00001). In 797 patients from 12 trials, pain at 24 hours favored dextromethorphan (MD -0.92; 95% CI: -1.24 to -0.60; p < 0.00001). Conclusions This meta-analysis suggests dextromethorphan use perioperatively reduces postoperative opioid consumption at 24-48 hours and pain scores at 1, 4-6, and 24 hours. PMID:26587683

  15. Perioperative Dextromethorphan as an Adjunct for Postoperative Pain: A Meta-analysis of Randomized Controlled Trials.

    PubMed

    King, Michael R; Ladha, Karim S; Gelineau, Amanda M; Anderson, T Anthony

    2016-03-01

    N-methyl-D-aspartate receptor antagonists have been shown to reduce perioperative pain and opioid use. The authors performed a meta-analysis to determine whether the use of perioperative dextromethorphan lowers opioid consumption or pain scores. PubMed, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Pubget, and EMBASE were searched. Studies were included if they were randomized, double-blinded, placebo-controlled trials written in English, and performed on patients 12 yr or older. For comparison of opioid use, included studies tracked total consumption of IV or intramuscular opioids over 24 to 48 h. Pain score comparisons were performed at 1, 4 to 6, and 24 h postoperatively. Difference in means (MD) was used for effect size. Forty studies were identified and 21 were eligible for one or more comparisons. In 848 patients from 14 trials, opioid consumption favored dextromethorphan (MD, -10.51 mg IV morphine equivalents; 95% CI, -16.48 to -4.53 mg; P = 0.0006). In 884 patients from 13 trials, pain at 1 h favored dextromethorphan (MD, -1.60; 95% CI, -1.89 to -1.31; P < 0.00001). In 950 patients from 13 trials, pain at 4 to 6 h favored dextromethorphan (MD, -0.89; 95% CI, -1.11 to -0.66; P < 0.00001). In 797 patients from 12 trials, pain at 24 h favored dextromethorphan (MD, -0.92; 95% CI, -1.24 to -0.60; P < 0.00001). This meta-analysis suggests that dextromethorphan use perioperatively reduces the postoperative opioid consumption at 24 to 48 h and pain scores at 1, 4 to 6, and 24 h.

  16. Dextromethorphan: a case study on addressing abuse of a safe and effective drug.

    PubMed

    Spangler, David C; Loyd, Catherine M; Skor, Emily E

    2016-06-23

    Dextromethorphan is a safe, effective cough suppressant, available without a prescription in the United States since 1958. Due to a perceived prevalence of abuse of dextromethorphan by teens, in 2007 the Drug Enforcement Administration requested the Food and Drug Administration evaluate whether dextromethorphan should be recommended for scheduling under the Controlled Substances Act. The Food and Drug Administration held an Advisory Committee meeting in 2010 to provide a scientific and medical evaluation of dextromethorphan and its abuse potential. To address reports of abuse, particularly by teens in the United States, the Consumer Healthcare Products Association initiated an abuse mitigation plan in 2010 with specific goals related to awareness of the behavior, perception of risk, social disapproval, and access to the products. In identifying abuse interventions, experts acknowledge that substance abuse among teens is a highly complex behavior and indicate that the best course of action is to address prevention by focusing on the factors that impact teen behavior. It is noteworthy that the annual prevalence of over-the-counter cough medicine abuse has sharply decreased since 2010. While a true cause-and-effect relationship cannot be assured, the Consumer Healthcare Products Association and its member companies believe that the increased awareness of the issue since the 2010 Food and Drug Administration Advisory Committee meeting, and the subsequent implementation of a well-delivered and targeted abuse mitigation plan that addressed the levers influencing teen decisions is contributing to the observed reduction in abuse. During the period of 2010-2015, reported abuse of dextromethorphan by 8(th), 10(th), and 12(th) graders decreased 35 %. The authors believe this reduction supports the view of the Consumer Healthcare Products Association at the outset of the abuse mitigation plan effort and today: Controlled substance scheduling or prescription requirements would

  17. Dextromethorphan- and pseudoephedrine-induced agitated psychosis and ataxia: case report.

    PubMed

    Roberge, R J; Hirani, K H; Rowland, P L; Berkeley, R; Krenzelok, E P

    1999-01-01

    Pseudoephedrine and dextromethorphan are therapeutic constituents of numerous commonly used, over-the-counter cough and cold preparations. Although this drug combination is generally considered quite safe if utilized in recommended doses, overmedication or overdose can result in serious neurologic and cardiovascular abnormalities that occasionally can be life-threatening. We present a case of a 2-year-old child who developed hyperirritability, psychosis, and ataxia after being overmedicated with a pseudoephedrine/dextromethorphan combination cough preparation, and discuss probable mechanisms of toxicity and risk factors for adverse events.

  18. Ovariectomy ameliorates dextromethorphan - induced memory impairment in young female rats

    PubMed Central

    Jahng, Jeong Won; Cho, Hee Jeong; Kim, Jae Goo; Kim, Nam Youl; Lee, Seoul; Lee, Yil Seob

    2006-01-01

    We have previously found that dextromethorphan (DM), over-the-counter cough suppressant, impairs memory retention in water maze task, when it is repeatedly administrated to adolescent female rats at high doses. In this study we examined first if ovariectomy ameliorates the DM-induced memory impairment in female rats, and then whether or not the DM effect is revived by estrogen replacement in ovariectomized female rats. Female rat pups received bilateral ovariectomy or sham operation on postnatal day (PND) 21, and then intraperitoneal DM (40 mg/kg) daily during PND 28–37. Rats were subjected to the Morris water maze task from PND 38, approximately 24 h after the last DM injection. In probe trial, goal quadrant dwell time was significantly reduced by DM in the sham operated group, however, the reduction by DM did not occur in the ovariectomy group. When 17β-estradiol was supplied to ovariectomized females during DM treatment, the goal quadrant dwell time was significantly decreased, compared to the vehicle control group. Furthermore, a major effect of estrogen replacement was found in the escape latency during the last 3 days of initial learning trials. These results suggest that ovariectomy may ameliorate the adverse effect of DM treatment on memory retention in young female rats, and that estrogen replacement may revive it, i.e. estrogen may take a major role in DM-induced memory impairment in female rats. PMID:16563229

  19. Estimation of the percolation thresholds in dextromethorphan hydrobromide matrices.

    PubMed

    Melgoza, L M; Rabasco, A M; Sandoval, H; Caraballo, I

    2001-02-01

    Percolation theory is a multidisciplinary theory that studies chaotic systems. It has been applied in the pharmaceutical field since 1987. Knowledge of the percolation threshold -- one of the most important concepts in percolation theory -- results in a clear improvement of the solid dosage form design. The percolation threshold is the concentration showing the maximum probability to obtain, for the first time, a percolating cluster of a substance. In this work, the percolation thresholds of dextromethorphan.HBr/Eudragit RS-PM inert matrices were estimated. The drug percolation threshold was estimated as 0.3691+/-0.0541 (P=0.05) of the total porosity (ranging between 23 and 36% w/w of drug). The SEM micrographs of the matrices are consistent with the estimated percolation range. In agreement with previous reports, different percolation thresholds were found for the matrix forming excipient Eudragit RS-PM. The site percolation threshold (based on the release properties) ranged between 10 and 20% v/v of the excipient, the site-bond percolation threshold (estimated from the mechanical properties) between 29.5 and 34% v/v of the excipient and the swelling percolation threshold between 34.3 and 46.9% v/v of the excipient. These percolation ranges are in agreement with those found previously for Eudragit RS-PM matrices containing naltrexone.HCl and morphine.HCl.

  20. Analysis of Dextromethorphan in Cough Drops and Syrups: A Medicinal Chemistry Laboratory

    ERIC Educational Resources Information Center

    Hamilton, Todd M.; Wiseman, Frank L., Jr.

    2009-01-01

    Fluorescence spectroscopy is used to determine the quantity of dextromethorphan hydrobromide (DM) in over-the-counter (OTC) cough drops and syrups. This experiment is appropriate for an undergraduate medicinal chemistry laboratory course when studying OTC medicines and active ingredients. Students prepare the cough drops and syrups for analysis,…

  1. Analysis of Dextromethorphan in Cough Drops and Syrups: A Medicinal Chemistry Laboratory

    ERIC Educational Resources Information Center

    Hamilton, Todd M.; Wiseman, Frank L., Jr.

    2009-01-01

    Fluorescence spectroscopy is used to determine the quantity of dextromethorphan hydrobromide (DM) in over-the-counter (OTC) cough drops and syrups. This experiment is appropriate for an undergraduate medicinal chemistry laboratory course when studying OTC medicines and active ingredients. Students prepare the cough drops and syrups for analysis,…

  2. The Treatment of the Behavioral Sequelae of Autism with Dextromethorphan: A Case Report

    ERIC Educational Resources Information Center

    Woodard, Cooper; Groden, June; Goodwin, Matthew; Shanower, Cori; Bianco, Joanne

    2005-01-01

    Dextromethorphan is the d-isomer of levorphenol, and an ingredient in antitussive preparations. A 10 year-old male diagnosed with Autistic Disorder, Pervasive Developmental Disorder, and Generalized Anxiety Disorder was administered this medication initially to treat a medical condition. This became a quasi-experimental ABAB design (A = baseline,…

  3. Spectrophotometric determination of pipazethate HCl, dextromethorphan HBr and drotaverine HCl in their pharmaceutical preparations.

    PubMed

    Amin, Alaa S; El-Sheikh, Ragaa; Zahran, Faten; Gouda, Ayman Abou El-fetouh

    2007-07-01

    A simple, accurate and highly sensitive spectrophotometric method is proposed for the rapid determination of pipazethate hydrochloride, dextromethorphan hydrobromide and drotaverine hydrochloride using chromotrope 2B (C2B) and chromotrope 2R (C2R). The method consists of extracting the formed ion-associates into chloroform in the case of pipazethate HCl and dextromethorphan HBr or into methylene chloride in the case of drotaverine HCl. The ion-associates exhibit absorption maxima at 528, 540 and 532 nm with C2B and at 526, 517 and 522 nm with C2R for pipazethate HCl, dextromethorphan HBr and drotaverine HCl, respectively. The calibration curves resulting from the measurements of absorbance-concentration relations (at the optimum reaction conditions) of the extracted ion-pairs are linear over the concentration range 4.36-52.32 microg mL(-1) for pipazethate, 3.7-48.15 microg mL(-1) for dextromethorphan and 4.34-60.76 microg mL(-1) for drotaverine, respectively. The effect of acidity, reagent concentration, time, solvent and stoichiometric ratio of the ion-associates were estimated. The molar absorptivity and Sandell sensitivity of the reaction products were calculated. Statistical treatment of the results reflects that the procedure is precise, accurate and easily applied for the determination of the drugs under investigation in pure form and in their pharmaceutical preparations.

  4. A Placebo Double-Blind Pilot Study of Dextromethorphan for Problematic Behaviors in Children with Autism

    ERIC Educational Resources Information Center

    Woodard, Cooper; Groden, June; Goodwin, Matthew; Bodfish, James

    2007-01-01

    We used a mixed group/single-case, double-blind, placebo-controlled, ABAB design to examine the safety and efficacy of the glutamate antagonist dextromethorphan for the treatment of problematic behaviors and core symptoms in eight children diagnosed with autism. All participants had increased levels of irritability at baseline as measured by the…

  5. A Placebo Double-Blind Pilot Study of Dextromethorphan for Problematic Behaviors in Children with Autism

    ERIC Educational Resources Information Center

    Woodard, Cooper; Groden, June; Goodwin, Matthew; Bodfish, James

    2007-01-01

    We used a mixed group/single-case, double-blind, placebo-controlled, ABAB design to examine the safety and efficacy of the glutamate antagonist dextromethorphan for the treatment of problematic behaviors and core symptoms in eight children diagnosed with autism. All participants had increased levels of irritability at baseline as measured by the…

  6. The Treatment of the Behavioral Sequelae of Autism with Dextromethorphan: A Case Report

    ERIC Educational Resources Information Center

    Woodard, Cooper; Groden, June; Goodwin, Matthew; Shanower, Cori; Bianco, Joanne

    2005-01-01

    Dextromethorphan is the d-isomer of levorphenol, and an ingredient in antitussive preparations. A 10 year-old male diagnosed with Autistic Disorder, Pervasive Developmental Disorder, and Generalized Anxiety Disorder was administered this medication initially to treat a medical condition. This became a quasi-experimental ABAB design (A = baseline,…

  7. Analysis of pharmacokinetic parameters for assessment of dextromethorphan metabolic phenotypes.

    PubMed

    Yeh, Geng-Chang; Tao, Pao-Luh; Ho, Hsiu-O; Lee, Yung-Jin; Chen, Julia Yi-Ru; Sheu, Ming-Thau

    2003-01-01

    In this study, the metabolic ratios of dextromethorphan to dextrorphan (DM/DX) in plasma were calculated at steady state after administering 2 dosage forms (Medicon) and Detusiv) of DM with different release rates. The urinary metabolic ratio for each subject was also determined based on the total drug concentration in the urine. An analysis of pharmacokinetic parameters for determining the DM metabolic phenotype was conducted. Results demonstrate that double logarithmic correlations between the metabolic ratios based on pharmacokinetic parameters of either AUC(0-tau,ss), C(max,ss), C(min,ss), or C(ave,ss) for Medicon and Detusiv and the urinary metabolic ratios were all significant. Probit plots of the metabolic ratios based on these pharmacokinetic parameters revealed 2 clusters of distribution, representing extensive and intermediate metabolizers. An antimode of 2.0 for total drug based on these pharmacokinetic parameters was determined and correspondingly referred to an antimode of 0.02 for the urinary metabolic ratio to delineate extensive and intermediate metabolizers. This model was also verified to be appropriate when using total plasma concentrations of DM and DX at any time during the period of the dosing interval at steady state to calculate the metabolic ratio for identifying extensive and intermediate metabolizers. Therefore, the metabolic ratio based on the pharmacokinetic parameters of either AUC(0-tau,ss), C(max,ss), C(min,ss), or C(ave,ss) and plasma concentrations of DM and DX in a single blood sample at steady state are proposed as an alternative way to identify phenotypes of CYP2D6. Copyright 2003 National Science Council, ROC and S. Karger AG, Basel

  8. Comparative Effects of Dextromethorphan and Dextrorphan on Nicotine Discrimination in Rats

    PubMed Central

    Wright, M. Jerry; Vann, Robert E.; Gamage, Thomas F.; Damaj, M. Imad; Wiley, Jenny L.

    2007-01-01

    While the role of dextrorphan and dextromethorphan as N-methyl-D-aspartate (NMDA) receptor antagonists has received considerable research attention, their effects on nicotinic acetylcholine receptors (nAChR) has been less well characterized. Recent in vitro and in vivo research has suggested that these drugs noncompetitively block α3β4*, α4β2, and α7 nAChR subtypes and antagonize nicotine’s antinociceptive and reinforcing effects. Both drugs were most potent at blocking α3β4* AChR. This study investigated the effects of dextrorphan and dextromethorphan on nicotine’s discriminative stimulus effects. Three groups of rats were trained in a two-lever drug discrimination procedure to discriminate 0.4 mg/kg s.c. nicotine from saline. Nicotine dose-dependently substituted for itself in all three groups. In contrast, when dextrorphan (group 1) or dextromethorphan (group 2) were injected i.p., neither substitution for nor antagonism of nicotine was observed for either drug. Since i.p. administration allows substantial metabolism of dextromethorphan to its parent compound dextrorphan, the two drugs were also tested following s.c. administration (group 3). Discrimination results were similar across both routes of administration, in that neither substitution nor antagonism occurred, however, s.c. administration reduced response rates to a much greater extent than did i.p. administration. Previous work suggests that β2 subunits are crucial for mediation of nicotine’s discriminative stimulus effects and may play a role in its reinforcing effects, albeit other research suggests a role for α3β4* nicotinic receptors in the latter. Our results suggest that α3β4* nicotinic receptors do not play a major role in nicotine’s discriminative stimulus effects. Further, they suggest that the role of cholinergic mediation of the behavioral effects of dextrorphan and dextromethorphan related to the abuse properties of nicotine may be minimal. PMID:17112574

  9. Low doses of dextromethorphan have a beneficial effect in the treatment of neuropathic pain.

    PubMed

    Morel, Véronique; Pickering, Gisèle; Etienne, Monique; Dupuis, Amandine; Privat, Anne-Marie; Chalus, Maryse; Eschalier, Alain; Daulhac, Laurence

    2014-12-01

    N-methyl-D-aspartate receptor (NMDAR) antagonists may be given in persistent neuropathic pain, but adverse events especially with ketamine may limit their clinical use. Less central and cognitive adverse events are described with dextromethorphan and memantine. These molecules have been explored in many preclinical and clinical studies, but data are conflicting as regards neuropathic pain alleviation. Dextromethorphan and memantine have been administered to animals after spinal nerve ligation (SNL) to evaluate their antinociceptive/cognitive effects and associated molecular events, including the phosphorylation of several tyrosine (pTyr(1336), pTyr(1472)) residues in the NR2B NMDAR subunit. Spinal nerve ligation and sham animals received dextromethorphan (10 mg/kg, i.p.), memantine (20 mg/kg, i.p.) or saline (1 mL/kg, i.p.). These drugs were administered once symptoms of allodynia and hyperalgesia had developed. Tests were carried out before and after surgery. Tactile allodynia, mechanical hyperalgesia and spatial memory were, respectively, evaluated by von Frey, Randall & Selitto and Y-maze tests and molecular events by Western blot analysis. Spinal nerve-ligated animals displayed nociception and impaired spatial memory. Dextromethorphan, but not memantine, reversed neuropathic pain (NP) symptoms, restored spatial memory integrity and decreased the expression of pTyr(1336)NR2B. Following postoperative administration of dextromethorphan, this study has demonstrated for the first time a concordance between behaviour, cognitive function and molecular events via pTyr(1336)NR2B for neuropathic pain alleviation. Confirmation of these findings in patients would constitute a major step forward in the treatment of neuropathic pain and in the improvement of cognitive function and quality of life. © 2014 Société Française de Pharmacologie et de Thérapeutique.

  10. Dextromethorphan-quinidine-responsive pseudobulbar affect (PBA): psychopharmacological model for wide-ranging disorders of emotional expression?

    PubMed

    Stahl, Stephen M

    2016-12-01

    The symptoms of emotional dysregulation associated with the syndrome known as pseudobulbar affect (PBA) can be effectively treated by the sigma, glutamate, and serotonergic agent dextromethorphan combined with quinidine. If the same brain circuits affected in PBA are also compromised in related disorders of emotional expression, dextromethorphan-quinidine and other novel sigma-glutamate-serotonin agents could prove to be novel psychopharmacologic treatments for these conditions as well.

  11. Co-administration of dextromethorphan and morphine: reduction of post-operative pain and lack of influence on morphine metabolism.

    PubMed

    Suski, Maciej; Bujak-Gizycka, Beata; Madej, Jozef; Kacka, Katarzyna; Dobrogowski, Jan; Woron, Jaroslaw; Olszanecki, Rafal; Korbut, Ryszard

    2010-08-01

    We investigated co-analgesic effect of dextromethorphan in adolescent post-operative patients with idiopathic scoliosis. In a double-blind study, 60 patients with ASA physical status I-II were randomised into two groups. Group dextromethorphan (n = 30; age: 15.9 +/- 2.4 years) was given oral dextromethorphan 30 or 45 mg 1 hr before surgery and 8, 20 and 32 hr after operation. Group placebo (n = 30; age: 16.5 +/- 2.7 years) received placebo at identical times. Post-operative analgesic requirements were assessed using nurse-controlled analgesia system. Pain was assessed using numeric rating scale before first administration of morphine and at 2, 3, 4, 6, 24 and 48 hr after operation. Blood samples were taken 20 min. after the first use of morphine (within 1 hr after operation). The total use of analgesics during surgery was lower in the dextromethorphan group. The dose of morphine providing relief immediately after surgery, as well as total analgesic requirements in the first and second day after surgery did not differ between groups. Subjectively evaluated pain intensity score (numeric rating scale) was lower for the dextromethorphan patients in the first 4 hr, but not later after surgery. Plasma levels of morphine, morphine-6-glucuronide and morphine-3-glucuronide did not differ between groups. Dextromethorphan did not influence morphine glucuronidation, in terms of promotion of formation of any morphine glucuronides. In conclusion, in young patients subjected to spine surgery, addition of dextromethorphan to morphine reduced pain only in early post-operative period. In such patients, co-analgesic action of dextromethorphan was not associated with significant changes in plasma levels of morphine metabolites.

  12. Effect of N-Methyl-D-Aspartate Receptor Antagonist Dextromethorphan on Opioid Analgesia in Pediatric Intensive Care Unit.

    PubMed

    Naeem, Mohammed; Al Alem, Hala; Al Shehri, Ali; Al-Jeraisy, Majed

    2016-01-01

    Objective. Pain control is an essential goal in the management of critical children. Narcotics are the mainstay for pain control. Patients frequently need escalating doses of narcotics. In such cases an adjunctive therapy may be beneficial. Dextromethorphan (DM) is NMDA receptor antagonist and may prevent tolerance to narcotics; however, its definitive role is still unclear. We sought whether dextromethorphan addition could decrease the requirements of fentanyl to control pain in critical children. Design. Double-blind, randomized control trial (RCT). Setting. Pediatric multidisciplinary ICU in tertiary care center. Patients. Thirty-six pediatric patients 2-14 years of age in a multidisciplinary PICU requiring analgesia were randomized into dextromethorphan and placebo. The subjects in both groups showed similarity in most of the characteristics. Interventions. Subjects while receiving fentanyl for pain control received dextromethorphan or placebo through nasogastric/orogastric tubes for 96 hours. Pain was assessed using FLACC and faces scales. Measurements and Main Results. This study found no statistical significant difference in fentanyl requirements between subjects receiving dextromethorphan and those receiving placebo (p = 0.127). Conclusions. Dextromethorphan has no effect on opioid requirement for control of acute pain in children admitted with acute critical care illness in PICU. The registration number for this trial is NCT01553435.

  13. Effect of N-Methyl-D-Aspartate Receptor Antagonist Dextromethorphan on Opioid Analgesia in Pediatric Intensive Care Unit

    PubMed Central

    Al Alem, Hala; Al Shehri, Ali; Al-Jeraisy, Majed

    2016-01-01

    Objective. Pain control is an essential goal in the management of critical children. Narcotics are the mainstay for pain control. Patients frequently need escalating doses of narcotics. In such cases an adjunctive therapy may be beneficial. Dextromethorphan (DM) is NMDA receptor antagonist and may prevent tolerance to narcotics; however, its definitive role is still unclear. We sought whether dextromethorphan addition could decrease the requirements of fentanyl to control pain in critical children. Design. Double-blind, randomized control trial (RCT). Setting. Pediatric multidisciplinary ICU in tertiary care center. Patients. Thirty-six pediatric patients 2–14 years of age in a multidisciplinary PICU requiring analgesia were randomized into dextromethorphan and placebo. The subjects in both groups showed similarity in most of the characteristics. Interventions. Subjects while receiving fentanyl for pain control received dextromethorphan or placebo through nasogastric/orogastric tubes for 96 hours. Pain was assessed using FLACC and faces scales. Measurements and Main Results. This study found no statistical significant difference in fentanyl requirements between subjects receiving dextromethorphan and those receiving placebo (p = 0.127). Conclusions. Dextromethorphan has no effect on opioid requirement for control of acute pain in children admitted with acute critical care illness in PICU. The registration number for this trial is NCT01553435. PMID:27867308

  14. The Therapeutic Effect of Adding Dextromethorphan to Clonidine for Reducing Symptoms of Opioid Withdrawal: A Randomized Clinical Trial

    PubMed Central

    Malek, Ayyoub; Amiri, Shahrokh; Habibi Asl, Bohlool

    2013-01-01

    Background. Dextromethorphan is a noncompetitive N-methyl D-aspartate receptor antagonist that is clinically feasible for relieving the opioid withdrawal symptoms. This study compares the efficacy of a combination therapy with dextromethorphan and clonidine to treatment with clonidine alone. Methods and Materials. In this double-blind randomized clinical trial, patients were selected from inpatients of detox and rehabilitation ward of Razi Hospital, Tabriz, Iran. They were randomly allocated to two groups receiving either clonidine (0.4–1.2 mg/day) or clonidine and dextromethorphan (300 mg/day). Withdrawal symptoms were evaluated in the first day of admission and again 24, 48, and 72 hours later. Results. Thirty male patients completed the trial in each group. Withdrawal symptoms began to decrease in the second day in patients receiving dextromethorphan and clonidine while patients receiving clonidine experienced the more severe symptoms in 72 hours. Analysis of variance of the symptom severity score revealed a significant group × time interaction (F = 14.25; P < 0.001), so that patients receiving dextromethorphan plus clonidine had milder symptoms during three days in all of the measurements compared to clonidine group. Conclusion. Combination therapy of dextromethorphan and clonidine would result in milder opioid withdrawal symptoms compared to clonidine alone with a reduction beginning at the second day. PMID:23864983

  15. Assessment of antitussive efficacy of dextromethorphan in smoking related cough: objective vs. subjective measures.

    PubMed

    Ramsay, James; Wright, Caroline; Thompson, Rachel; Hull, David; Morice, Alyn H

    2008-05-01

    Dextromethorphan is widely used as a cough suppressant in over the counter medications. Its efficacy in altering cough reflex sensitivity has been shown in healthy volunteers. In contrast evidence for an effect on clinically important cough is poor. A significant decrease in evoked cough was seen with dextromethorphan compared with placebo. However, both placebo and active treatment improved subjective data to a similar degree. We doubt the validity of currently used objective tests in the investigation of antitussives. Using an established model of smokers cough we measured the antitussive effects of dextromethorphan compared with placebo. The study was a randomized, double-blind placebo controlled, crossover comparison of 22 mg 0.8 ml(-1) dextromethorphan delivered pregastrically with matched placebo. Objective and subjective measurements of cough were recorded. Subjective measures included a daily diary record of cough symptoms and the Leicester quality of life questionnaire. Cough frequency was recorded using a manual cough counter. The objective measure of cough reflex sensitivity was the citric acid, dose-response cough challenge. Dextromethorphan was significantly associated with an increase in the concentration of citric acid eliciting an average of two coughs/inhalation (C2) when compared with placebo, 1 h post dose by 0.49 mM (95% CI 0.05, 0.45, geometric mean 3.09) compared with placebo 0.24 mM (geometric mean 1.74) P < 0.05 and at 2 h 0.57 mM (95% CI 0.01, 0.43, geometric mean 3.75) compared with placebo 0.34 mM (geometric mean 2.19) P < 0.05). There was a highly significant improvement in the subjective data when compared with baseline. However, there was no significant difference between placebo and active treatment. No correlation was seen between cough sensitivity to citric acid and recorded cough counts or symptoms. When both subjective and objective data were compared with screening data there was evidence of a marked 'placebo' effect. The

  16. Assessment of antitussive efficacy of dextromethorphan in smoking related cough: objective vs. subjective measures

    PubMed Central

    Ramsay, James; Wright, Caroline; Thompson, Rachel; Hull, David; Morice, Alyn H

    2008-01-01

    AIMS Using an established model of smokers cough we measured the antitussive effects of dextromethorphan compared with placebo. METHODS The study was a randomized, double-blind placebo controlled, crossover comparison of 22 mg 0.8 ml−1 dextromethorphan delivered pregastrically with matched placebo. Objective and subjective measurements of cough were recorded. Subjective measures included a daily diary record of cough symptoms and the Leicester quality of life questionnaire. Cough frequency was recorded using a manual cough counter. The objective measure of cough reflex sensitivity was the citric acid, dose–response cough challenge. RESULTS Dextromethorphan was significantly associated with an increase in the concentration of citric acid eliciting an average of two coughs/inhalation (C2) when compared with placebo, 1 h post dose by 0.49 mM (95% CI 0.05, 0.45, geometric mean 3.09) compared with placebo 0.24 mM (geometric mean 1.74) P < 0.05 and at 2 h 0.57 mM (95% CI 0.01, 0.43, geometric mean 3.75) compared with placebo 0.34 mM (geometric mean 2.19) P < 0.05). There was a highly significant improvement in the subjective data when compared with baseline. However, there was no significant difference between placebo and active treatment. No correlation was seen between cough sensitivity to citric acid and recorded cough counts or symptoms. When both subjective and objective data were compared with screening data there was evidence of a marked ‘placebo’ effect. CONCLUSIONS The objective measure of cough sensitivity demonstrates dextromethorphan effectively diminishes the cough reflex sensitivity. However, subjective measures do not support this. Other studies support these findings, which may represent a profound sensitivity of the cough reflex to higher influences. WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Dextromethorphan is widely used as a cough suppressant in over the counter medications. Its efficacy in altering cough reflex sensitivity has been shown in

  17. Comparison of various urine collection intervals for caffeine and dextromethorphan phenotyping in children.

    PubMed

    Kennedy, Mary Jayne; Abdel-Rahman, Susan M; Kashuba, Angela D M; Leeder, J Steven

    2004-07-01

    Caffeine and dextromethorphan have been used successfully both alone and in combination to assess phenotype and enzyme activity in children of various ages. Previous pediatric phenotyping studies with these agents have used varying durations of urine collection. However, the minimum duration required for accurate phenotypic assessment with these compounds in children remains unknown. We calculated the cumulative metabolite recoveries and molar ratios in urine collected from children for 2, 4, 6, and 8 hours after caffeine and dextromethorphan administration to determine when respective urinary molar ratios stabilize and thus likely accurately reflect enzyme activity. Subjects (n = 24, ages 3-8 years) were given 4 oz of Coca-Cola(R) ( approximately 11.5 mg caffeine) and a single oral dose of dextromethorphan (0.5 mg/kg). Urine was collected at discrete intervals (0-2, 2-4, 4-6, and 6-8 h) during an 8-hour period, and the cumulative metabolite recoveries and urinary molar ratios were calculated. CYP2D6 genotyping was also performed in 21 of 24 subjects. In CYP2D6 extensive metabolizers, the extent of recovery for relevant metabolites was equivalent by 4 hours and represented 45% to 60% of the total amount recovered in the 8-hour period. The 2-hour CYP1A2 ratio was significantly different from those of longer collection intervals. Metabolite ratios for all other enzymes (i.e., NAT-2, XO, and CYP2D6) were independent of the duration of urine collection. These data suggest that a 4-hour urine collection is adequate for the concurrent assessment of hepatic CYP1A2, NAT-2, XO, and CYP2D6 activity in children ages 3 to 8 years who are CYP2D6 extensive metabolizers, using standard caffeine and dextromethorphan phenotyping methods. Longer collection periods may be required, however, in younger children or CYP2D6 poor metabolizers.

  18. Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illness

    DTIC Science & Technology

    2015-07-01

    trials in humans with low dose naltrexone have established benefits in syndromes related to Gulf War Illness such as fibromyalgia. We have successfully...sectional epidemiologic study. JAMA. 1997:15;277:231-7. Younger J, Noor N, McCue R, Mackey S. Low - dose naltrexone for the treatment of fibromyalgia...is related to low grade neuron-inflammation, which can be down regulated, by Naltrexone and Dextromethorphan. This is untested but potentially

  19. Evaluation of the reinforcing and subjective effects of heroin in combination with dextromethorphan and quinidine

    PubMed Central

    Vosburg, Suzanne K.; Sullivan, Maria A.; Comer, Sandra D.

    2015-01-01

    Objective Studies have suggested that the N-methyl-d-aspartate antagonist dextromethorphan may be useful in the treatment of opioid dependence. Design This double-blinded, placebo-controlled inpatient study evaluated the effects of 0, 30, and 60 mg of dextromethorphan and quinidine (DMQ) on the reinforcing and subjective effects of heroin in recently detoxified heroin abusers. Participants Nine heroin-dependent participants were admitted and then detoxified from heroin over the course of several days. Interventions Participants were subsequently stabilized on 0, 30, or 60 mg of DMQ. Each dose of DMQ was administered for two consecutive weeks, and the effects of heroin (0, 12.5, and 50 mg) were studied under each DMQ maintenance dose condition. DMQ and heroin dose were administered in random order both within and between participants. Results Planned comparisons revealed statistically significant increases in progressive ratio breakpoint values and positive subjective ratings as a function of heroin dose. There were no consistent changes in any of the responses as a function of DMQ maintenance dose, other than a modest reduction in craving. Conclusions In summary, results from this study suggest that maintenance on dextromethorphan in combination with quinidine has a limited role in the treatment of opioid dependence. PMID:22320027

  20. Development and validation of dissolution study of sustained release dextromethorphan hydrobromide tablets.

    PubMed

    Rajan, Sekar; Colaco, Socorrina; Ramesh, N; Meyyanathan, Subramania Nainar; Elango, K

    2014-02-01

    This study describes the development and validation of dissolution tests for sustained release Dextromethorphan hydrobromide tablets using an HPLC method. Chromatographic separation was achieved on a C18 column utilizing 0.5% triethylamine (pH 7.5) and acetonitrile in the ratio of 50:50. The detection wavelength was 280 nm. The method was validated and response was found to be linear in the drug concentration range of 10-80 microg mL(-1). The suitable conditions were clearly decided after testing sink conditions, dissolution medium and agitation intensity. The most excellent dissolution conditions tested, for the Dextromethorphan hydrobromide was applied to appraise the dissolution profiles. The method was validated and response was found to be linear in the drug concentration range of 10-80 microg mL(-1). The method was established to have sufficient intermediate precision as similar separation was achieved on another instrument handled by different operators. Mean Recovery was 101.82%. Intra precisions for three different concentrations were 1.23, 1.10 0.72 and 1.57, 1.69, 0.95 and inter run precisions were % RSD 0.83, 1.36 and 1.57%, respectively. The method was successfully applied for dissolution study of the developed Dextromethorphan hydrobromide tablets.

  1. Evaluation of the reinforcing and subjective effects of heroin in combination with dextromethorphan and quinidine.

    PubMed

    Vosburg, Suzanne K; Sullivan, Maria A; Comer, Sandra D

    2011-01-01

    Studies have suggested that the N-methyl-D-aspartate antagonist dextromethorphan may be useful in the treatment of opioid dependence. This double-blinded, placebo-controlled inpatient study evaluated the effects of 0, 30, and 60 mg of dextromethorphan and quinidine (DMQ) on the reinforcing and subjective effects of heroin in recently detoxified heroin abusers. Nine heroin-dependent participants were admitted and then detoxified from heroin over the course of several days. Participants were subsequently stabilized on 0, 30, or 60 mg of DMQ. Each dose of DMQ was administered for two consecutive weeks, and the effects of heroin (0, 12.5, and 50 mg) were studied under each DMQ maintenance dose condition. DMQ and heroin dose were administered in random order both within and between participants. Planned comparisons revealed statistically significant increases in progressive ratio breakpoint values and positive subjective ratings as a function of heroin dose. There were no consistent changes in any of the responses as a function of DMQ maintenance dose, other than a modest reduction in craving. In summary, results from this study suggest that maintenance on dextromethorphan in combination with quinidine has a limited role in the treatment of opioid dependence.

  2. Neurodevelopmental Outcome and Treatment Efficacy of Benzoate and Dextromethorphan in Siblings with Attenuated Nonketotic Hyperglycinemia.

    PubMed

    Bjoraker, Kendra J; Swanson, Michael A; Coughlin, Curtis R; Christodoulou, John; Tan, Ee S; Fergeson, Mark; Dyack, Sarah; Ahmad, Ayesha; Friederich, Marisa W; Spector, Elaine B; Creadon-Swindell, Geralyn; Hodge, M Antoinette; Gaughan, Sommer; Burns, Casey; Van Hove, Johan L K

    2016-03-01

    To evaluate the impact of sodium benzoate and dextromethorphan treatment on patients with the attenuated form of nonketotic hyperglycinemia. Families were recruited with 2 siblings both affected with attenuated nonketotic hyperglycinemia. Genetic mutations were expressed to identify residual activity. The outcome on developmental progress and seizures was compared between the first child diagnosed and treated late with the second child diagnosed at birth and treated aggressively from the newborn period using dextromethorphan and benzoate at dosing sufficient to normalize plasma glycine levels. Both siblings were evaluated with similar standardized neurodevelopmental measures. In each sibling set, the second sibling treated from the neonatal period achieved earlier and more developmental milestones, and had a higher developmental quotient. In 3 of the 4 sibling pairs, the younger sibling had no seizures whereas the first child had a seizure disorder. The adaptive behavior subdomains of socialization and daily living skills improved more than motor skills and communication. Early treatment with dextromethorphan and sodium benzoate sufficient to normalize plasma glycine levels is effective at improving outcome if used in children with attenuated disease with mutations providing residual activity and when started from the neonatal period. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  3. MK-801 and dextromethorphan block microglial activation and protect against methamphetamine-induced neurotoxicity.

    PubMed

    Thomas, David M; Kuhn, Donald M

    2005-07-19

    Methamphetamine causes long-term toxicity to dopamine nerve endings of the striatum. Evidence is emerging that microglia can contribute to the neuronal damage associated with disease, injury, or inflammation, but their role in methamphetamine-induced neurotoxicity has received relatively little attention. Lipopolysaccharide (LPS) and the neurotoxic HIV Tat protein, which cause dopamine neuronal toxicity after direct infusion into brain, cause activation of cultured mouse microglial cells as evidenced by increased expression of intracellular cyclooxygenase-2 and elevated secretion of tumor necrosis factor-alpha. MK-801, a non-competitive NMDA receptor antagonist that is known to protect against methamphetamine neurotoxicity, prevents microglial activation by LPS and HIV Tat. Dextromethorphan, an antitussive agent with NMDA receptor blocking properties, also prevents microglial activation. In vivo, MK-801 and dextromethorphan reduce methamphetamine-induced activation of microglia in striatum and they protect dopamine nerve endings against drug-induced nerve terminal damage. The present results indicate that the ability of MK-801 and dextromethorphan to protect against methamphetamine neurotoxicity is related to their common property as blockers of microglial activation.

  4. Dextromethorphan Addiction Mediated Through the NMDA System: Common Pathways With Alcohol?

    PubMed

    Roy, A Kenison; Hsieh, Chenen; Crapanzano, Kathleen

    2015-01-01

    Dextromethorphan, an antitussive (cough suppressant) drug of the morphinan class with sedative and dissociative properties found in cough syrup and other over-the-counter products, is also a substance of abuse, seen primarily in young adults all over the world. A case of dextromethorphan use disorder is presented in a 45-year-old women. Her repeated attempts at abstinence were unsuccessful secondary to continued intense cravings. Treatment with topiramate resulted in complete resolution of her cravings. Topiramate was chosen empirically because of a common action with dextromethorphan in the NMDA system. Genetic testing was obtained and the patient was found to be a carrier of the GRIK1 rs2832407(C:C) allele. The (C:C) allele has been associated with an increased risk of alcohol use disorder and a treatment response of patients with heavy drinking to topiramate. This case provides an opportunity to discuss personalized medicine (treatment options aided by the use of genetic testing) and the possible shared genetic susceptibility for dependence in 2 substances of abuse.

  5. Dextromethorphan/quinidine sulfate (Zenvia) for Pseudobulbar Affect

    PubMed Central

    Rosen, Howard

    2010-01-01

    SUMMARY A new agent containing a combination of Dextromethorphan and Quinidine is currently under development for the treatment of pseudobulbar affect (PBA). PBA is a disorder of emotional regulation, characterized by uncontrollable outbursts of laughing and/or crying that are disproportionate to the emotions being experienced. The pathophysiology of PBA is currently unknown, although the disorder is thought to occur exclusively in the setting of neurological disease. The most influential theory on PBA posits that emotional outbursts are being generated in the brainstem autonomously due to loss of regulatory control by the frontal lobes. Although rarely life-threatening, PBA can have significant impact on patients’ quality of life and thus merits treatment. There are currently no approved treatments for PBA. Several agents have been found to be effective in small placebo-controlled trials and case series, with the most commonly used agents being tricyclic antidepressants and selective serotonin reuptake inhibitors. Both these treatments are inexpensive and relatively low-risk, although the quality and quantity of the available data on their efficacy are not optimal. DM has several pharmacological mechanisms of action relevant to the brain. It is an NMDA-receptor antagonist, which prompted investigators to study its potential for slowing progression in ALS, where glutamate toxicity is thought to be a factor. The combination agent DM/Q was developed to slow the metabolism of DM by P450 2D6 enzymes in the liver. DM/Q was not effective in slowing ALS progression, but patients noted that it helped to control their emotional outbursts, suggesting it might be useful as a treatment for PBA. DM is also a sigma1 receptor agonist. These receptors are widely distributed in the brain, but probably most heavily in the limbic system, suggesting that DM may exert its emotion-controlling effects via these receptors. The endogenous ligands for sigma1 receptors are not altogether

  6. The effect of dextromethorphan in preventing cholecalciferol-induced poison shyness and sickness-induced anorexia in the laboratory Norway rat.

    PubMed

    Gould, Elaine M; Holmes, Selena J

    2008-02-01

    Overcoming bait and poison shyness is critical to the success of pest control operations against rats and other rodents. The authors hypothesized that the N-methyl-D-aspartate receptor blocker, dextromethorphan, could prevent the acquired memory of sickness and sickness-induced anorexia resulting from rodents eating poisoned bait. Cholecalciferol (1/4 LD(50)) was mixed with dextromethorphan and fed to rats on two 2 day sessions, with an 18 day break in between. Dextromethorphan did not prevent poison shyness; during the second poisoning period, both the cholecalciferol only and the cholecalciferol plus dextromethorphan groups had lower intakes of the bait compared with the control and dextromethorphan only groups. In addition to the previously recorded symptoms of cholecalciferol poisoning, the rats in this trial were observed to have nose bleeds, weepy eyes, laboured breathing and, in the case of the cholecalciferol only treated group, a period of decreased water intake followed by a period of increased water intake. There was also a period of increased water intake in the cholecalciferol plus dextromethorphan group. Dextromethorphan failed to prevent poison shyness and the anorectic effect of cholecalciferol. However, it did reduce anorexia from 17 days in the cholecaliferol group to 8 days in the cholecalciferol plus dextromethorphan group.

  7. Effect of dextromethorphan on human K(v)1.3 channel activity: involvement of C-type inactivation.

    PubMed

    Lee, Jun-Ho; Choi, Sun-Hye; Shin, Tae-Joon; Lee, Byung-Hwan; Hwang, Sung-Hee; Kim, Hyoung-Chun; Nah, Seung-Yeol

    2011-01-25

    Dextromethorphan exhibits neuroprotective effects against inflammation-mediated neurodegeneration. However, relatively little is known regarding the molecular mechanism for this inflammation-mediated neuroprotection. Human K(v)1.3 channels, one of the voltage-gated potassium channels, are widely expressed in the immune and nervous systems. Activation of human K(v)1.3 channels causes neuroglia-mediated neurodegeneration. Agents that inhibit human K(v)1.3 channel activity have been developed as novel drugs for immunosuppression. In the present study, we investigated the effects of dextromethorphan on human K(v)1.3 or K(v)1.2 channel activity heterologously expressed in Xenopus laevis oocytes. The channel currents were measured with the two-electrode voltage clamp technique. Activation of both channels induced outward peak and steady-state currents. Dextromethorphan treatment induced a slight inhibition of peak currents in human K(v)1.2 and K(v)1.3 channels, whereas dextromethorphan profoundly inhibited the steady-state currents of human K(v)1.3 channels compared to K(v)1.2 channel currents. Dextromethorphan's action on steady-state currents of human K(v)1.3 channels was in a concentration-dependent manner. The half-maximal inhibitory concentration (IC(50)) on steady-state currents of human K(v)1.3 channels was 12.8±1.6μM. Dextromethorphan also accelerated the C-type inactivation rate, increased the current decay rate, and inhibited currents in a use-dependent manner. These results indicate that dextromethorphan accelerates C-type inactivation of human K(v)1.3 channels and acts as an open-channel blocker. These results further suggest the possibility that dextromethorphan-mediated acceleration of C-type inactivation of human K(v)1.3 channels might be one of the cellular bases of dextromethorphan-mediated protection against inflammation-mediated neurodegeneration. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Clinical assessment of CYP2D6-mediated herb-drug interactions in humans: Effects of milk thistle, black cohosh, goldenseal, kava kava, St. John's wort, and Echinacea

    PubMed Central

    Gurley, Bill J.; Swain, Ashley; Hubbard, Martha A.; Williams, D. Keith; Barone, Gary; Hartsfield, Faith; Tong, Yudong; Carrier, Danielle J.; Cheboyina, Shreekar; Battu, Sunil K.

    2007-01-01

    Cytochrome P450 2D6 (CYP2D6), an important CYP isoform with regard to drug-drug interactions, accounts for the metabolism of ∼30% of all medications. To date, few studies have assessed the effects of botanical supplementation on human CYP2D6 activity in vivo. Six botanical extracts were evaluated in three separate studies (2 extracts per study), each incorporating 18 healthy volunteers (9 females). Subjects were randomized to receive a standardized botanical extract for 14 days on separate occasions. A 30-day washout period was interposed between each supplementation phase. In study 1, subjects received milk thistle (Silybum marianum) and black cohosh (Cimicifuga racemosa). In study 2, kava kava (Piper methysticum), and goldenseal (Hydrastis canadensis) extracts were administered, and in study 3 subjects received St. John's wort (Hypericum perforatum) and Echinacea (Echinacea purpurea). The CYP2D6 substrate, debrisoquine (5 mg), was administered before and at the end of supplementation. Pre- and post-supplementation phenotypic trait measurements were determined for CYP2D6 using 8-hour debrisoquine urinary recovery ratios (DURR). Comparisons of pre- and post-supplementation DURR revealed significant inhibition (∼50%) of CYP2D6 activity for goldenseal, but not for the other extracts. Accordingly, adverse herb-drug interactions may result with concomitant ingestion of goldenseal supplements and drugs that are CYP2D6 substrates. PMID:18214849

  9. Effect of Dextromethorphan-Quinidine on Agitation in Patients With Alzheimer Disease Dementia: A Randomized Clinical Trial.

    PubMed

    Cummings, Jeffrey L; Lyketsos, Constantine G; Peskind, Elaine R; Porsteinsson, Anton P; Mintzer, Jacobo E; Scharre, Douglas W; De La Gandara, Jose E; Agronin, Marc; Davis, Charles S; Nguyen, Uyen; Shin, Paul; Tariot, Pierre N; Siffert, João

    Agitation is common among patients with Alzheimer disease; safe, effective treatments are lacking. To assess the efficacy, safety, and tolerability of dextromethorphan hydrobromide-quinidine sulfate for Alzheimer disease-related agitation. Phase 2 randomized, multicenter, double-blind, placebo-controlled trial using a sequential parallel comparison design with 2 consecutive 5-week treatment stages conducted August 2012-August 2014. Patients with probable Alzheimer disease, clinically significant agitation (Clinical Global Impressions-Severity agitation score ≥4), and a Mini-Mental State Examination score of 8 to 28 participated at 42 US study sites. Stable dosages of antidepressants, antipsychotics, hypnotics, and antidementia medications were allowed. In stage 1, 220 patients were randomized in a 3:4 ratio to receive dextromethorphan-quinidine (n = 93) or placebo (n = 127). In stage 2, patients receiving dextromethorphan-quinidine continued; those receiving placebo were stratified by response and rerandomized in a 1:1 ratio to dextromethorphan-quinidine (n = 59) or placebo (n = 60). The primary end point was change from baseline on the Neuropsychiatric Inventory (NPI) Agitation/Aggression domain (scale range, 0 [absence of symptoms] to 12 [symptoms occur daily and with marked severity]). A total of 194 patients (88.2%) completed the study. With the sequential parallel comparison design, 152 patients received dextromethorphan-quinidine and 127 received placebo during the study. Analysis combining stages 1 (all patients) and 2 (rerandomized placebo nonresponders) showed significantly reduced NPI Agitation/Aggression scores for dextromethorphan-quinidine vs placebo (ordinary least squares z statistic, -3.95; P < .001). In stage 1, mean NPI Agitation/Aggression scores were reduced from 7.1 to 3.8 with dextromethorphan-quinidine and from 7.0 to 5.3 with placebo. Between-group treatment differences were significant in stage 1 (least squares mean

  10. Determination of dextromethorphan in human plasma using pipette tip solid-phase extraction and gas chromatography-mass spectrometry.

    PubMed

    Hasegawa, Chika; Kumazawa, Takeshi; Uchigasaki, Seisaku; Lee, Xiao-Pen; Sato, Keizo; Terada, Masaru; Kurosaki, Kunihiko

    2011-10-01

    Dextromethorphan was extracted from human plasma samples (100 μL) using MonoTip C(18) tips, which are packed with C(18)-bonded monolithic silica gel that is attached to the inside of the tip. The samples, which contained dextromethorphan and trimeprazine as an internal standard (IS), were mixed with 200 μL of distilled water and 50 μL of 1 mol/L glycine-sodium hydroxide buffer (pH 10). The mixture was extracted to the C(18) phase of the tip by 20 sequential aspirating/dispensing cycles using a manual micropipettor. The analytes retained on the C(18) phase were then eluted with methanol by five sequential aspirating/dispensing cycles. The eluate was injected directly into a gas chromatograph and detected by a mass spectrometer with selected ion monitoring in positive electron ionization mode. An Equity-5 fused silica capillary column (30 m × 0.32 mm i.d., film thickness 0.5 μm) gave adequate separation of the dextromethorphan, IS, and impurities. The recoveries of dextromethorphan and the IS spiked into plasma were >87.4%. The regression equation for dextromethorphan showed excellent linearity from 2.5 to 320 ng/mL of plasma, and the limit of detection was 1.25 ng/mL of plasma. The intraday and interday coefficients of variation were less than 10.5% and 14.7%, respectively. The accuracy ranged from 91.9% to 107%. The validated method was successfully used to quantify the plasma concentration of dextromethorphan in a human subject after oral administration of the drug. © Springer-Verlag 2011

  11. Dextromethorphan and debrisoquine metabolism and polymorphism of the gene for cytochrome P450 isozyme 2D50 in Thoroughbreds.

    PubMed

    Corado, Carley R; McKemie, Daniel S; Knych, Heather K

    2016-09-01

    OBJECTIVE To characterize polymorphisms of the gene for cytochrome P450 isozyme 2D50 (CYP2D50) and the disposition of 2 CYP2D50 probe drugs, dextromethorphan and debrisoquine, in horses. ANIMALS 23 healthy horses (22 Thoroughbreds and 1 Standardbred). PROCEDURES Single-nucleotide polymorphisms (SNPs) in CYP2D50 were identified. Disposition of dextromethorphan (2 mg/kg) and debrisoquine (0.2 mg/kg) were determined after oral (dextromethorphan) or nasogastric (debrisoquine) administration to the horses. Metabolic ratios of plasma dextromethorphan and total dextrorphan (dextrorphan plus dextrorphan-O-β-glucuronide) and 4-hydroxydebrisoquine concentrations were calculated on the basis of the area under the plasma concentration-versus-time curve extrapolated to infinity for the parent drug divided by that for the corresponding metabolite. Pharmacokinetic data were used to categorize horses into the phenotypic drug-metabolism categories poor, extensive, and ultrarapid. Disposition patterns were compared among categories, and relationships between SNPs and metabolism categories were explored. RESULTS Gene sequencing identified 51 SNPs, including 27 nonsynonymous SNPs. Debrisoquine was minimally detected after oral administration. Disposition of dextromethorphan varied markedly among horses. Metabolic ratios for dextromethorphan ranged from 0.03 to 0.46 (mean, 0.12). On the basis of these data, 1 horse was characterized as a poor metabolizer, 18 were characterized as extensive metabolizers, and 3 were characterized as ultrarapid metabolizers. CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that CYP2D50 is polymorphic and that the disposition of the probe drug varies markedly in horses. The polymorphisms may be related to rates of drug metabolism. Additional research involving more horses of various breeds is needed to fully explore the functional implication of polymorphisms in CYP2D50.

  12. New potentiometric and spectrophotometric methods for the determination of dextromethorphan in pharmaceutical preparations.

    PubMed

    Elmosallamy, Mohamed A F; Amin, Alaa S

    2014-01-01

    New, simple and convenient potentiometric and spectrophotometric methods are described for the determination of dextromethorphan hydrobromide (DXM) in pharmaceutical preparations. The potentiometric technique is based on developing a potentiometric sensor incorporating the dextromethorphan tetrakis(p-chlorophenyl)borate ion-pair complex as an electroactive species in a plasticized PVC matrix membrane with o-nitophenyl octyl ether or dioctyl phthalate. The sensor shows a rapid near Nernstian response of over 1 × 10(-5) - 1 × 10(-2) mol L(-1) dextromethorphan in the pH range of 3.0 - 9.0. The detection limit is 2 × 10(-6) mol L(-1) DXM and the response time is instantaneous (2 s). The proposed spectrophotometric technique involves the reaction of DXM with eriochrom black T (EBT) to form an ion-associate complex. Solvent extraction is used to improve the selectivity of the method. The optimal extraction and reaction conditions have been studied, and the analytical characteristics of the method have been obtained. Linearity is obeyed in the range of 7.37 - 73.7 × 10(-5) mol L(-1) DXM, and the detection limit of the method is 1.29 × 10(-5) mol L(-1). The relative standard deviation (RSD) and relative error for six replicate measurements of 3.685 × 10(-4) mol L(-1) are 0.672 and 0.855%, respectively. The interference effect of some excepients has also been tested. The drug contents in pharmaceutical preparations were successfully determined by the proposed methods by applying the standard-addition technique.

  13. Serum dextromethorphan/dextrorphan metabolic ratio for CYP2D6 phenotyping in clinical practice.

    PubMed

    Jurica, J; Bartecek, R; Zourkova, A; Pindurova, E; Sulcova, A; Kasparek, T; Zendulka, O

    2012-08-01

    Accurate prediction of actual CYP2D6 metabolic activity may prevent some adverse drug reactions and improve therapeutic response in patients receiving CYP2D6 substrates. Dextromethorphan-to-dextrorphan metabolic ratio (MR(DEM/DOR)) is well established as a marker of CYP2D6 metabolizer status. The relationship between urine and plasma or serum MR(DEM/DOR) is not well established nor is there evidence of antimode for separation of intermediate and especially poor metabolizers (PM) from extensive metabolizers (EM). This study addressed whether CYP2D6 phenotyping using molar metabolic ratio of dextromethorphan to dextrorphan (MR(DEM/DOR)) in serum is usable and reliable in clinical practice as urinary MR(DEM/DOR). We measured MR(DEM/DOR) in serum and CYP2D6 genotype in 51 drug-naive patients and 30 volunteers. Receiver-operator characteristic (ROC) analysis was used for the evaluation of optimum cut-off value for discriminating between extensive, intermediate and PM. In addition, we studied the correlation of serum MR(DEM/DOR) with urine MR(DEM/DOR) in the 30 healthy volunteers. A trimodal distribution of log MR(DEM/DOR) in serum was observed, with substantial overlap between extensive and intermediate metabolizer groups. We obtained an acceptable cut-off serum MR(DEM/DOR) value to discriminate between PM and either extensive or extensive + intermediate metabolizers. Using serum MR(DEM/DOR), it seems to be unreliable to discriminate EM from intermediate metabolizers (IM). A strong correlation between serum MR(DEM/DOR) and urine MR(DEM/DOR) was found. Serum MR(DEM/DOR) (3 h) correlated with MR(DEM/DOR) in urine (0-8 h). Serum MR(DEM/DOR) discriminated between extensive and PM and between extensive + intermediate and PM. Our CYP2D6 phenotyping using serum dextromethorphan/dextrorphan molar ratio appears reliable but requires independent validation. © 2012 Blackwell Publishing Ltd.

  14. Beneficial effects of co-treatment with dextromethorphan on prenatally methadone-exposed offspring.

    PubMed

    Chiang, Yao-Chang; Ye, Li-Ci; Hsu, Kuei-Ying; Liao, Chien-Wei; Hung, Tsai-Wei; Lo, Wan-Jou; Ho, Ing-Kang; Tao, Pao-Luh

    2015-03-20

    Heroin use among young women of reproductive age has drawn much attention around the world. Although methadone is widely used in maintenance therapy for heroin/morphine addiction, the long-term effects of prenatal exposure to methadone and preventative therapy remain unclear. For revealing this question, female pregnant Sprague-Dawley rats were sub-grouped to receive (1) vehicle, (2) methadone 5 mg/kg at embryonic day 3 (E3) and then 7 mg/kg from E4 to E20, (3) dextromethorphan (DM) 3 mg/kg, and (4) methadone + DM (the rats received methadone followed by DM treatment), subcutaneously, twice a day from E3 to E20. The body weight, natural withdrawal, pain sensitivity, ED50, conditioned place preference and water maze were conducted at different postnatal stages (P1 to P79) of offspring. The quantitative real-time RT-PCR and electrophysiology were also used to measure the gene expression of opioid receptors in the spinal cord and changes of LTP/LTD in the hippocampus, separately. Prenatal exposure to methadone or DM did not affect survival rate, body weight, water maze and LTP or LTD of offspring. However, prenatal methadone significantly increased the withdrawal symptoms, pain sensitivity, addiction liability and decreased the mRNA expression of pain related opioid receptors. Co-administration of DM with methadone in the maternal rats effectively prevented these abnormalities of offspring induced by methadone. Our study clearly showed that co-administration of dextromethorphan with methadone in the maternal rats prevented the adverse effects induced by prenatal methadone exposure. It implies that dextromethorphan may have a potential to be used in combination with methadone for maintenance treatment in pregnant heroin-addicted women to prevent the adverse effects induced by methadone on offspring.

  15. Simultaneous quantitative analysis of dextromethorphan, dextrorphan and chlorphenamine in human plasma by liquid chromatography-electrospray tandem mass spectrometry.

    PubMed

    Ding, Ying; Huang, Kai; Chen, Lan; Yang, Jie; Xu, Wen-Yan; Xu, Xue-Jiao; Duan, Ru; Zhang, Jing; He, Qing

    2014-03-01

    A sensitive and accurate HPLC-MS/MS method was developed for the simultaneous determination of dextromethorphan, dextrorphan and chlorphenamine in human plasma. Three analytes were extracted from plasma by liquid-liquid extraction using ethyl acetate and separated on a Kromasil 60-5CN column (3 µm, 2.1 × 150 mm) with mobile phase of acetonitrile-water (containing 0.1% formic acid; 50:50, v/v) at a flow rate of 0.2 mL/min. Quantification was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring mode using positive electrospray ionization. The calibration curve was linear over the range of 0.01-5 ng/mL for dextromethorphan, 0.02-5 ng/mL for dextrorphan and 0.025-20 ng/mL for chlorphenamine. The lower limits of quantification for dextromethorphan, dextrorphan and chlorphenamine were 0.01, 0.02 and 0.025 ng/mL, respectively. The intra- and inter-day precisions were within 11% and accuracies were in the range of 92.9-102.5%. All analytes were proved to be stable during sample storage, preparation and analytic procedures. This method was first applied to the pharmacokinetic study in healthy Chinese volunteers after a single oral dose of the formulation containing dextromethorphan hydrobromide (18 mg) and chlorpheniramine malaeate (8 mg).

  16. The Abuse of Dextromethorphan-Based Cough Syrup: A Pilot Study of the Community of Waynesboro, Pennsylvania.

    ERIC Educational Resources Information Center

    Momodou, N. Darboe; And Others

    1996-01-01

    Discusses the emergence of a new type of abused drug, dextromethorphan, which is used in cough syrup. Presents the results of the first phase of a comprehensive investigation of this phenomenon in the Waynesboro, Pa. school district. Survey data indicate abuse of cough syrup has increased over the years and is increasingly perceived as a problem…

  17. Simultaneous determination of pseudoephedrine hydrochloride, chlorpheniramine maleate, and dextromethorphan hydrobromide by second-derivative photodiode array spectroscopy.

    PubMed

    Murtha, J L; Julian, T N; Radebaugh, G W

    1988-08-01

    The simultaneous determination of the active ingredients in multicomponent pharmaceutical products normally requires the use of a separation technique, such as HPLC or GC, followed by quantitation. Presented here is a rapid, validated, analytical method that does not require prior separation for the simultaneous determination of three drugs, pseudoephedrine hydrochloride, chlorpheniramine maleate, and dextromethorphan hydrobromide, in a tablet formulation. A diode array spectrophotometer, capable of multicomponent analysis, was used for the quantitation. The utility of this method was demonstrated in two ways: the analysis of a chewable pediatric tablet (formulation CP) containing 7.5 mg of pseudoephedrine hydrochloride, 0.5 mg of chlorpheniramine maleate, and 2.5 mg of dextromethorphan hydrobromide, and the dissolution analysis of a hydroxypropyl methylcellulose-based sustained-release tablet (formulation SR) containing 120 mg of pseudoephedrine hydrochloride, 8 mg of chlorpheniramine maleate, and 60 mg of dextromethorphan hydrobromide. The sensitivity of this assay is 7.5 micrograms/mL for pseudoephedrine hydrochloride, 1.0 micrograms/mL for chlorpheniramine maleate, and 5.0 micrograms/mL for dextromethorphan hydrobromide, using the second-derivative spectra of the absorbance with respect to wavelength. Determinations were made in 0.1 M sodium acetate buffer at pH 5.0 using a 1-cm quartz cell. Absorbance spectra, and their first and second derivatives, from 240 to 300 nm were used for the determination. The results obtained by this method compared favorably with the results obtained by a validated HPLC method.

  18. A Placebo-Controlled Trial of Dextromethorphan as an Adjunct in Opioid-Dependent Patients Undergoing Methadone Maintenance Treatment

    PubMed Central

    Lee, Sheng-Yu; Chen, Shiou-Lan; Chang, Yun-Hsuan; Chu, Chun-Hsien; Chen, Shih-Heng; Chen, Po See; Huang, San-Yuan; Tzeng, Nian-Sheng; Wang, Liang-Jen; Lee, I Hui; Wang, Tzu-Yun; Chen, Kao Chin; Yang, Yen Kuang; Hong, Jau-Shyong

    2015-01-01

    Background: Low-dose dextromethorphan (DM) might have anti-inflammatory and neurotrophic effects mechanistically remote from an NMDA receptor. In a randomized, double-blind, controlled 12 week study, we investigated whether add-on dextromethorphan reduced cytokine levels and benefitted opioid-dependent patients undergoing methadone maintenance therapy (MMT). Methods: Patients were randomly assigned to a group: DM60 (60mg/day dextromethorphan; n = 65), DM120 (120mg/day dextromethorphan; n = 65), or placebo (n = 66). Primary outcomes were the methadone dose required, plasma morphine level, and retention in treatment. Plasma tumor necrosis factor (TNF)-α, C-reactive protein, interleukin (IL)-6, IL-8, transforming growth factor–β1, and brain-derived neurotrophic factor (BDNF) levels were examined during weeks 0, 1, 4, 8, and 12. Multiple linear regressions with generalized estimating equation methods were used to examine the therapeutic effect. Results: After 12 weeks, the DM60 group had significantly longer treatment retention and lower plasma morphine levels than did the placebo group. Plasma TNF-α was significantly decreased in the DM60 group compared to the placebo group. However, changes in plasma cytokine levels, BDNF levels, and the methadone dose required in the three groups were not significantly different. Conclusions: We provide evidence—decreased concomitant heroin use—of low-dose add-on DM’s efficacy for treating opioid-dependent patients undergoing MMT. PMID:25716777

  19. The Abuse of Dextromethorphan-Based Cough Syrup: A Pilot Study of the Community of Waynesboro, Pennsylvania.

    ERIC Educational Resources Information Center

    Momodou, N. Darboe; And Others

    1996-01-01

    Discusses the emergence of a new type of abused drug, dextromethorphan, which is used in cough syrup. Presents the results of the first phase of a comprehensive investigation of this phenomenon in the Waynesboro, Pa. school district. Survey data indicate abuse of cough syrup has increased over the years and is increasingly perceived as a problem…

  20. A placebo-controlled trial of dextromethorphan as an adjunct in opioid-dependent patients undergoing methadone maintenance treatment.

    PubMed

    Lee, Sheng-Yu; Chen, Shiou-Lan; Chang, Yun-Hsuan; Chu, Chun-Hsien; Chen, Shih-Heng; Chen, Po See; Huang, San-Yuan; Tzeng, Nian-Sheng; Wang, Liang-Jen; Lee, I Hui; Wang, Tzu-Yun; Chen, Kao Chin; Yang, Yen Kuang; Hong, Jau-Shyong; Lu, Ru-Band

    2015-02-25

    Low-dose dextromethorphan (DM) might have anti-inflammatory and neurotrophic effects mechanistically remote from an NMDA receptor. In a randomized, double-blind, controlled 12 week study, we investigated whether add-on dextromethorphan reduced cytokine levels and benefitted opioid-dependent patients undergoing methadone maintenance therapy (MMT). Patients were randomly assigned to a group: DM60 (60mg/day dextromethorphan; n = 65), DM120 (120mg/day dextromethorphan; n = 65), or placebo (n = 66). Primary outcomes were the methadone dose required, plasma morphine level, and retention in treatment. Plasma tumor necrosis factor (TNF)-α, C-reactive protein, interleukin (IL)-6, IL-8, transforming growth factor-β1, and brain-derived neurotrophic factor (BDNF) levels were examined during weeks 0, 1, 4, 8, and 12. Multiple linear regressions with generalized estimating equation methods were used to examine the therapeutic effect. After 12 weeks, the DM60 group had significantly longer treatment retention and lower plasma morphine levels than did the placebo group. Plasma TNF-α was significantly decreased in the DM60 group compared to the placebo group. However, changes in plasma cytokine levels, BDNF levels, and the methadone dose required in the three groups were not significantly different. We provide evidence-decreased concomitant heroin use-of low-dose add-on DM's efficacy for treating opioid-dependent patients undergoing MMT. © The Author 2015. Published by Oxford University Press on behalf of CINP.

  1. Stimulant methamphetamine and dextromethorphan use among Thai adolescents: implications for health of women and children.

    PubMed

    Chomchai, Chulathida; Manaboriboon, Boonying

    2012-09-01

    For over a decade, amphetamine-type stimulants have made their way into the adolescent culture of Thailand. Coupled with the more recent emergence of the legal, over-the-counter cough medicine dextromethorphan (DM), they represent the most commonly abused substances among Thai youths today. Methamphetamine is the second most popular drug of abuse in Thailand, the first being cannabis. It is available in the crystalline version, ICE, and the less pure methamphetamine tablets. The tablets are frequently crushed and smoked. Its use has gained enormous popularity among teenagers and young adults, including women of child-bearing age. As such, it has become the most common drug being detected in the urine of peripartum women, resulting in peripartum and postpartum complications for both mother and child. DM is a newer drug which has gained popularity among middle school and high school students due to its easy availability as a single product over the counter. It is usually taken with soft drinks at parties and gathering. It is metabolized by CYP4502D6 to dextrorphan, the substance responsible for the feeling of euphoria. Consequently, those who are poor metabolizers often experience the "negative" effects associated with the drug. The recreational use of methamphetamine and dextromethorphan in teenagers and young adults in Thailand is a serious problem. Recognizing not only the toxicological but also the emotional and psychosocial impacts of these drugs on Thai youth is an integral part of approaching the problem.

  2. Effects of dextromethorphan on rats' acquisition of responding with delayed reinforcement.

    PubMed

    Morgan, Thomas; Porritt, Matthew; Poling, Alan

    2006-11-01

    Separate groups of 16 rats received 0, 40, 60, or 80 mg/kg dextromethorphan prior to a 2-h response-acquisition session during which responses on one lever produced food (reinforcement lever, RL, responses) after a 15-s resetting delay and responses on the other lever cancelled food deliveries earned by RL responses, but otherwise had no programmed consequences. When compared to the 0 mg/kg dose, the 40, 60, and 80 mg/kg doses significantly decreased the latency to the tenth RL response, which has been used previously as an index of response acquisition [Pallares, MA, Nadal, RA, Silvestro, JS, Ferre, NS. Effects of ketamine, a noncompetitive NMDA antagonist, on the acquisition of the lever-press response in rats. Physio Behav 1995; 57:389-392.]. Only the 80 mg/kg dose, however, significantly reduced the total number of food pellets earned, the total number of RL responses, or the total number of rats that met the criterion for response acquisition. The present results indicate that dextromethorphan can disrupt initial response acquisition (i.e., learning) with positive reinforcement, although the dose that did so depended on the measure used to index performance. Moreover, the effects of the drug did not appear to reflect specific learning impairment, but rather more general disruption of behavior.

  3. Rationale and design of a multicenter randomized clinical trial with memantine and dextromethorphan in ketamine-responder patients.

    PubMed

    Pickering, Gisèle; Pereira, Bruno; Morel, Véronique; Tiberghien, Florence; Martin, Elodie; Marcaillou, Fabienne; Picard, Pascale; Delage, Noémie; de Montgazon, Géraldine; Sorel, Marc; Roux, Delphine; Dubray, Claude

    2014-07-01

    The N-methyl-D-aspartate receptor plays an important role in central sensitization of neuropathic pain and N-methyl-D-aspartate receptor antagonists, such as ketamine, memantine and dextromethorphan may be used for persistent pain. However, ketamine cannot be repeated too often because of its adverse events. A drug relay would be helpful in the outpatient to postpone or even cancel the next ketamine infusion. This clinical trial evaluates if memantine and/or dextromethorphan given as a relay to ketamine responders may maintain or induce a decrease of pain intensity and have a beneficial impact on cognition and quality of life. This trial is a multi-center, randomized, controlled and single-blind clinical study (NCT01602185). It includes 60 ketamine responder patients suffering from neuropathic pain. They are randomly allocated to memantine, dextromethorphan or placebo. After ketamine infusion, 60 patients received either memantine (maximal dose 20 mg/day), or dextromethorphan (maximal dose 90 mg/day), or placebo for 12 weeks. The primary endpoint is pain measured on a (0-10) Numeric Rating Scale 1 month after inclusion. Secondary outcomes include assessment of neuropathic pain, sleep, quality of life, anxiety/depression and cognitive function at 2 and 3 months. Data analysis is performed using mixed models and the tests are two-sided, with a type I error set at α=0.05. This study will explore if oral memantine and/or dextromethorphan may be a beneficial relay in ketamine responders and may diminish ketamine infusion frequency. Preservation of cognitive function and quality of life is also a central issue that will be analyzed in these vulnerable patients. Copyright © 2014. Published by Elsevier Inc.

  4. A double-blind, placebo-controlled trial of dextromethorphan combined with clonidine in the treatment of heroin withdrawal.

    PubMed

    Lin, Shih-Ku; Pan, Chun-Hung; Chen, Chia-Hui

    2014-08-01

    Dextromethorphan has been reported to ameliorate opioid withdrawal symptoms in both animal and human subjects. In the present study, we investigated the efficacy of dextromethorphan as an add-on medication in heroin detoxification treatment in a double-blind, placebo-controlled design. Sixty-five heroin-dependent patients (male, 63; female, 2) participated in this inpatient detoxification trial after giving informed consent. Clonidine 0.075 mg 4 times a day was given as an antiwithdrawal medication at baseline. Each patient was then randomly assigned to treatment with either dextromethorphan 60 mg or placebo 4 times a day as additional medication. Flurazepam 30 mg was given before bedtime for insomnia. Other medications that were allowed included loperamide for diarrhea and lorazepam for agitation. Participants were monitored using the Objective Opioid Withdrawal Scale 3 times a day as the primary outcome to compare drug efficacy between groups. Generalized estimating equation model analysis revealed that the Objective Opioid Withdrawal Scale had no group difference between dextromethorphan and placebo group overall (P = 0.29), whereas a significant difference between groups was found during day 3 to day 6 (P = 0.04) by post hoc analysis. There was no difference in the Clinical Global Impression Scale, patient's impression of treatment, and use of ancillary medications between groups. No severe adverse effects were noticed. We suggest that dextromethorphan has some beneficial effect in attenuating the severity of opioid withdrawal symptoms and can be used as an adjunction medication in the treatment of opioid withdrawal, whereas the exact efficacy needs further investigation.

  5. Rationale and design of a randomized double-blind clinical trial in breast cancer: dextromethorphan in chemotherapy-induced peripheral neuropathy.

    PubMed

    Martin, Elodie; Morel, Véronique; Joly, Dominique; Villatte, Christine; Delage, Noémie; Dubray, Claude; Pereira, Bruno; Pickering, Gisèle

    2015-03-01

    Anti-cancer chemotherapy often induces peripheral neuropathy and consequent cognitive and quality of life impairment. Guidelines recommend antiepileptics or antidepressants but their efficacy is limited.Dextromethorphan, a N-methyl-D-aspartate receptor antagonist, has shown its efficacy in painful diabetic neuropathy and in post-operative pain but has not been studied in chemotherapy-induced peripheral neuropathy. This clinical trial evaluates the effect of dextromethorphan on pain, cognition and quality of life in patients who suffer from neuropathic pain induced by chemotherapy for breast cancer. It also assesses the impact of dextromethorphan genetic polymorphism on analgesia. This trial is a randomized, placebo-controlled, double-blind clinical study in two parallel groups (NCT02271893). It includes 40 breast cancer patients suffering from chemotherapy-induced peripheral neuropathy. They are randomly allocated to dextromethorphan (maximal dose 90 mg/day) or placebo for 4 weeks. The primary endpoint is pain intensity measured after 4 weeks of treatment on a (0-10) Numeric Pain Rating Scale. Secondary outcomes include assessment of neuropathic pain, cognitive function, anxiety/depression, sleep and quality of life. Data analysis is performed using mixed models and the tests are two-sided, with a type I error set at α=0.05. Considering the poor efficacy of available drugs in chemotherapy-induced neuropathic pain, dextromethorphan may be a valuable therapeutic option. Pharmacogenetics may provide predictive factors of dextromethorphan response in patients suffering from breast cancer. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. A study of potential pharmacokinetic and pharmacodynamic interactions between dextromethorphan/quinidine and memantine in healthy volunteers.

    PubMed

    Pope, Laura E; Schoedel, Kerri A; Bartlett, Cynthia; Sellers, Edward M

    2012-08-01

    Dextromethorphan/quinidine (DMQ) is the first agent indicated for the treatment of pseudobulbar affect. Dextromethorphan, the active ingredient, is a low-affinity, uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. This study evaluated the potential for a drug-drug interaction (DDI) of DMQ with memantine, which is also an NMDA receptor antagonist. This open-label, randomized, parallel-group study enrolled healthy adults who were randomized into one of two treatment groups. Group 1 subjects were administered memantine at a starting dose of 5 mg once daily, which was titrated over a 3-week period to a dose of 10 mg twice daily (every 12 hours) and continued for another 11 days to attain steady state; DMQ 30 mg (dextromethorphan 30 mg/quinidine 30 mg) every 12 hours was then added for a further 8 days. Group 2 subjects received DMQ 30 mg every 12 hours for 8 days to attain steady state; memantine was then added, titrated on the same schedule as in group 1, and continued at 10 mg every 12 hours for an additional 11 days. Pharmacokinetic blood sampling was performed to assess the primary endpoints of the 90% confidence intervals (CIs) for the geometric mean ratios of the areas under the plasma concentration-time curves (AUCs) for memantine, dextromethorphan, dextrorphan - the dextromethorphan metabolite - and quinidine during concomitant therapy versus monotherapy. Safety/tolerability and pharmacodynamic variables were also assessed. A total of 52 subjects were randomized. In both group 1 (n = 23) and group 2 (n = 29), the 90% CIs for the ratios of the AUCs during concomitant therapy versus monotherapy were within the predefined range to indicate similarity (0.8-1.25) for memantine, dextromethorphan and dextrorphan, indicating no pharmacokinetic DDI. The 90% CI for the AUC ratio for quinidine was slightly above the predefined range; however, the mean AUC increased by only 25%. In both groups, incidence of adverse events was similar, and pharmacodynamic

  7. The Effects of Dextromethorphan on Driving Performance and the Standardized Field Sobriety Test.

    PubMed

    Perry, Paul J; Fredriksen, Kristian; Chew, Stephanie; Ip, Eric J; Lopes, Ingrid; Doroudgar, Shadi; Thomas, Kelan

    2015-09-01

    Dextromethorphan (DXM) is abused most commonly among adolescents as a recreational drug to generate a dissociative experience. The objective of the study was to assess driving with and without DXM ingestion. The effects of one-time maximum daily doses of DXM 120 mg versus a guaifenesin 400 mg dose were compared among 40 healthy subjects using a crossover design. Subjects' ability to drive was assessed by their performance in a driving simulator (STISIM® Drive driving simulator software) and by conducting a standardized field sobriety test (SFST) administered 1-h postdrug administration. The one-time dose of DXM 120 mg did not demonstrate driving impairment on the STISIM® Drive driving simulator or increase SFST failures compared to guaifenesin 400 mg. Doses greater than the currently recommended maximum daily dose of 120 mg are necessary to perturb driving behavior. © 2015 American Academy of Forensic Sciences.

  8. Dextromethorphan: An update on its utility for neurological and neuropsychiatric disorders.

    PubMed

    Nguyen, Linda; Thomas, Kelan L; Lucke-Wold, Brandon P; Cavendish, John Z; Crowe, Molly S; Matsumoto, Rae R

    2016-03-01

    Dextromethorphan (DM) is a commonly used antitussive and is currently the only FDA-approved pharmaceutical treatment for pseudobulbar affect. Its safety profile and diverse pharmacologic actions in the central nervous system have stimulated new interest for repurposing it. Numerous preclinical investigations and many open-label or blinded clinical studies have demonstrated its beneficial effects across a variety of neurological and psychiatric disorders. However, the optimal dose and safety of chronic dosing are not fully known. This review summarizes the preclinical and clinical effects of DM and its putative mechanisms of action, focusing on depression, stroke, traumatic brain injury, seizure, pain, methotrexate neurotoxicity, Parkinson's disease and autism. Moreover, we offer suggestions for future research with DM to advance the treatment for these and other neurological and psychiatric disorders. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. High-dose dextromethorphan produces myelinoid bodies in the hippocampus of rats.

    PubMed

    Tran, Hai-Quyen; Chung, Yoon Hee; Shin, Eun-Joo; Kim, Won Ki; Lee, Jae-Chul; Jeong, Ji Hoon; Wie, Myung Bok; Jang, Choon-Gon; Yamada, Kiyofumi; Nabeshima, Toshitaka; Kim, Hyoung-Chun

    2016-10-01

    Dextromethorphan (DM) administered at supra-antitussive doses produce psychotoxic and neurotoxic effects in humans. We administered DM (80 mg/kg) to rats intraperitoneally to determine the ultrastructural change induced by DM, because intraperitoneal route is sensitive for the behavioral responses. Treatment with DM resulted in mitochondrial dysfunction and formation of myelinoid bodies in the hippocampus. MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate] attenuated DM-induced cytosolic oxidative burdens. However, neither MK-801 nor naloxone affected DM-induced mitochondrial dysfunction and formation of myelinoid bodies, indicating that the neurotoxic mechanism needs to be further elucidated. Therefore, the spectrum of toxicological effects associated with DM need to be reassessed. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  10. Simultaneous determination of dextromethorphan, diphenhydramine and phenylephrine in expectorant and decongestant syrups by capillary electrophoresis.

    PubMed

    Gomez, María R; Olsina, Roberto A; Martínez, Luis D; Silva, María F

    2002-10-15

    The separation of basic nitrogenous compounds commonly used as active ingredients in cold medicine formulations by micellar electrokinetic capillary chromatography and capillary zone electrophoresis with direct absorptiometric detection was investigated. The type and composition of the background electrolyte (BGE) were investigated with respect to separation selectivity and BGE stability. BGE of 10 mM sodium dihydrogenphosphate-sodium tetraborate buffer containing 10 mM SDS and 10% acetonitrile, pH 9.0 was found to be optimal. Dextromethorphan hydrobhromide, diphenhydramine hydrochloride and phenylephrine hydrochloride were baseline-separated in less than 11 min, giving separation efficiencies of up to 494,000 theoretical plates, reproducibility of corrected peaks areas below 3% relative standard deviation and concentration detection limits from 2.5 to 5.5 microg ml(-1). Detection was performed at 196 and 214 nm.

  11. A randomized placebo controlled trial to evaluate the effects of butamirate and dextromethorphan on capsaicin induced cough in healthy volunteers

    PubMed Central

    Faruqi, Shoaib; Wright, Caroline; Thompson, Rachel; Morice, Alyn H

    2014-01-01

    Aims The examination of cough reflex sensitivity through inhalational challenge can be utilized to demonstrate pharmacological end points. Here we compare the effect of butamirate, dextromethorphan and placebo on capsaicin-induced cough in healthy volunteers. Methods In this randomized, placebo-controlled, six way crossover study the effect of dextromethrophan 30 mg, four doses of butamirate and placebo was evaluated on incremental capsaicin challenges performed at baseline and 2, 4, 6, 8, 12 and 24 h following dosing. The primary end point was the area under the curve (AUC(0,12h)) of log10 C5 from pre-dose to 12 h after dosing. Plasma butamirate metabolites were analyzed to evaluate pharmacokinetic and pharmacodynamic relationships. Results Thirty-four subjects (13 males, median age 25 years) completed the study. Cough sensitivity decreased from baseline in all arms of the study. Dextromethorphan was superior to placebo (P = 0.01) but butamirate failed to show significant activity with maximum attenuation at the 45 mg dose. There was no apparent relationship between pharmacokinetic and pharmacodynamic parameters for butamirate. Conclusions We have demonstrated for the first time that dextromethorphan attenuates capsaicin challenge confirming its broad activity on the cough reflex. The lack of efficacy of butamirate could be due to formulation issues at higher doses. PMID:24995954

  12. A randomized placebo controlled trial to evaluate the effects of butamirate and dextromethorphan on capsaicin induced cough in healthy volunteers.

    PubMed

    Faruqi, Shoaib; Wright, Caroline; Thompson, Rachel; Morice, Alyn H

    2014-12-01

    The examination of cough reflex sensitivity through inhalational challenge can be utilized to demonstrate pharmacological end points. Here we compare the effect of butamirate, dextromethorphan and placebo on capsaicin-induced cough in healthy volunteers. In this randomized, placebo-controlled, six way crossover study the effect of dextromethrophan 30 mg, four doses of butamirate and placebo was evaluated on incremental capsaicin challenges performed at baseline and 2, 4, 6, 8, 12 and 24 h following dosing. The primary end point was the area under the curve (AUC(0,12h)) of log10 C5 from pre-dose to 12 h after dosing. Plasma butamirate metabolites were analyzed to evaluate pharmacokinetic and pharmacodynamic relationships. Thirty-four subjects (13 males, median age 25 years) completed the study. Cough sensitivity decreased from baseline in all arms of the study. Dextromethorphan was superior to placebo (P = 0.01) but butamirate failed to show significant activity with maximum attenuation at the 45 mg dose. There was no apparent relationship between pharmacokinetic and pharmacodynamic parameters for butamirate. We have demonstrated for the first time that dextromethorphan attenuates capsaicin challenge confirming its broad activity on the cough reflex. The lack of efficacy of butamirate could be due to formulation issues at higher doses. © 2014 The British Pharmacological Society.

  13. Dextromethorphan and caffeine as probes for simultaneous determination of debrisoquin-oxidation and N-acetylation phenotypes in children.

    PubMed

    Evans, W E; Relling, M V; Petros, W P; Meyer, W H; Mirro, J; Crom, W R

    1989-05-01

    The feasibility and reliability of simultaneously determining debrisoquin oxidation and N-acetylation phenotypes was assessed in children with use of two innocuous substrate probes given by mouth, 30 mg dextromethorphan (Pertussin ES) and 25 to 46 mg caffeine (Coca-Cola beverage). Twenty-six children and adolescents (aged 3 to 21 years) were studied three times, once with each substrate given alone and once with the two substrates given together. Urine was collected for 4 hours, and the molar urinary metabolic ratios for dextromethorphan:dextrorphan and for two caffeine metabolites (AFMU:1X) were determined by HPLC ultraviolet assays. The urinary metabolic ratios for both substrates were not significantly different when the substrates were given alone compared with when they were given together. There also was no difference in either the oxidation or acetylation phenotype assignments when the two substrates were given alone and when they were given together. No adverse effects were observed. We conclude that dextromethorphan and caffeine can be given together to simultaneously determine oxidation and acetylation phenotypes and can thereby provide an innocuous, noninvasive method for the assessment of polymorphic drug metabolism in various pediatric populations.

  14. Assessment of the effect of dextromethorphan and ketamine on the acute nociceptive threshold and wind-up of the second pain response in healthy male volunteers

    PubMed Central

    Hughes, A M; Rhodes, J; Fisher, G; Sellers, M; Growcott, J W

    2002-01-01

    Aims The aim of this study was to assess the efficacy of dextromethorphan and ketamine relative to placebo on the acute nociceptive threshold and wind-up of second pain response in healthy male volunteers. Methods The trial was a randomized, double-blind, placebo-controlled, three period crossover, double dummy design in 12 healthy male volunteers. During each of the three periods (which were separated by a 1 week washout period) each volunteer received either a single oral dose of 0.7 mg kg−1 dextromethorphan and placebo to ketamine, or placebo to dextromethorphan followed by a single intravenous injection of 0.375 mg kg−1 ketamine, or placebo to both dextromethorphan and ketamine. The trial did not schedule administration of both ketamine and dextromethorphan together. Acute nociceptive thresholds and wind-up of second pain were measured in the skin of the thenar eminence of the ventral surfaces of the right and left hands, using a SOMEDIC™ thermotest apparatus, before and at the estimated tmax for dextromethorphan (i.e. 2.15 h). Blood pressure and heart rate were also monitored before dosing and after the dosing regimen. Results Neither dextromethorphan nor ketamine had any significant effect on acute nociceptive thresholds on either hand (P>0.05). Moreover, dextromethorphan was without any significant effect (P>0.05) on the wind-up of the second pain response on either hand. The lsmean number of stimuli tolerated vs placebo (95% confidence intervals of the difference in number of stimuli in parentheses) were 15.84 vs 16.48 (−5.52, 4.24) and 11.75 vs 15.25 (−11.89, 4.90) for left- and right-hand, respectively, following dextromethorphan administration. In contrast ketamine produced significant reductions in wind-up to second pain in both the left and right hands (P=0.0002 and 0.0386, respectively). The lsmean numbers of stimuli tolerated vs placebo (95% confidence intervals of the difference in number of stimuli in parentheses) were 28.41 vs 16.48 (6

  15. To compare the effect of dextromethorphan, promethazine and placebo on nocturnal cough in children aged 1-12 y with upper respiratory infections: a randomized controlled trial.

    PubMed

    Bhattacharya, Malobika; Joshi, Neha; Yadav, Sangita

    2013-11-01

    To evaluate whether promethazine and dextromethorphan reduce nocturnal cough and improve sleep quality in children aged 1-12 y with upper respiratory tract infection (URI). This randomised double-blinded placebo-controlled trial was conducted in Pediatric outpatient department of Lok Nayak Hospital, Delhi. After randomization into promethazine, dextromethorphan and placebo groups, parental assessment of 120 children with URI for nocturnal cough severity (child), post-tussive vomiting (child) and sleep quality (child and parent) on the night before enrolment and after 3 d of assigned medication was measured using an internally validated indigenously prepared ordinal scale. Entire cohort improved in all the study parameters after 3 d. However, no superior benefit was noted when individual parameters were compared in the promethazine and dextromethorphan groups with the placebo group. Adverse effects were more frequent in the dextromethorphan and promethazine groups although the difference was not statistically significant. Nocturnal cough in URI is self-resolving and dextromethorphan and promethazine prescribed for the same are not superior to placebo.

  16. Molecularly imprinted polymer cartridges coupled on-line with high performance liquid chromatography for simple and rapid analysis of dextromethorphan in human plasma samples.

    PubMed

    Moein, Mohammad Mahdi; Javanbakht, Mehran; Akbari-Adergani, Behrouz

    2011-04-01

    In this paper, a novel method is described for automated determination of dextromethorphan in biological fluids using molecularly imprinted solid-phase extraction (MISPE) as a sample clean-up technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and dextromethorphan as template molecule. These imprinted polymers were used as solid-phase extraction sorbent for the extraction of dextromethorphan from human plasma samples. Various parameters affecting the extraction efficiency of the MIP cartridges were evaluated. The high selectivity of the sorbent coupled to the high performance liquid chromatographic system permitted a simple and rapid analysis of this drug in plasma samples with limits of detection (LOD) and quantification (LOQ) of 0.12 ng/mL and 0.35 ng/mL, respectively. The MIP selectivity was evaluated by analyzing of the dextromethorphan in presence of several substances with similar molecular structures and properties. Results from the HPLC analyses showed that the recoveries of dextromethorphan using MIP cartridges from human plasma samples in the range of 1-50 ng/mL were higher than 87%. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Anti-dyskinetic mechanisms of amantadine and dextromethorphan in the 6-OHDA rat model of Parkinson’s disease: role of NMDA vs. 5-HT1A receptors

    PubMed Central

    Paquette, Melanie A.; Martinez, Alex A.; Macheda, Teresa; Meshul, Charles K.; Johnson, Steven W.; Berger, S. Paul; Giuffrida, Andrea

    2013-01-01

    Amantadine and dextromethorphan suppress levodopa (L-DOPA)-induced dyskinesia (LID) in patients with Parkinson’s disease (PD) and abnormal involuntary movements (AIMs) in the unilateral 6-hydroxydopamine (6-OHDA) rat model. These effects have been attributed to N-methyl-d-aspartate (NMDA) antagonism. However, amantadine and dextromethorphan are also thought to block serotonin (5-HT) uptake and cause 5-HT overflow, leading to stimulation of 5-HT1A receptors, which has been shown to reduce LID. We undertook a study in 6-OHDA rats to determine whether the anti-dyskinetic effects of these two compounds are mediated by NMDA antagonism and/or 5-HT1A agonism. In addition, we assessed the sensorimotor effects of these drugs using the Vibrissae-Stimulated Forelimb Placement and Cylinder tests. Our data show that the AIM-suppressing effect of amantadine was not affected by the 5-HT1A antagonist WAY-100635, but was partially reversed by the NMDA agonist d-cycloserine. Conversely, the AIM-suppressing effect of dextromethorphan was prevented by WAY-100635 but not by d-cycloserine. Neither amantadine nor dextromethorphan affected the therapeutic effects of L-DOPA in sensorimotor tests. We conclude that the anti-dyskinetic effect of amantadine is partially dependent on NMDA antagonism, while dextromethorphan suppresses AIMs via indirect 5-HT1A agonism. Combined with previous work from our group, our results support the investigation of 5-HT1A agonists as pharmacotherapies for LID in PD patients. PMID:22861201

  18. Dextromethorphan overdose

    MedlinePlus

    ... Blurred vision Coma Constipation Convulsions (seizures) Drowsiness Dizziness Hallucinations High or low blood pressure Muscle twitches Nausea ... this medicine to "feel good" and to have hallucinations. Like other drugs of abuse, this can be ...

  19. An extension of hypotheses regarding rapid-acting, treatment-refractory, and conventional antidepressant activity of dextromethorphan and dextrorphan.

    PubMed

    Lauterbach, Edward C

    2012-06-01

    It was previously hypothesized that dextromethorphan (DM) and dextrorphan (DX) may possess antidepressant properties, including rapid and conventional onsets of action and utility in treatment-refractory depression, based on pharmacodynamic similarities to ketamine. These similarities included sigma-1 (σ(1)) agonist and NMDA antagonist properties, calcium channel blockade, muscarinic binding, serotonin transporter (5HTT) inhibition, and μ receptor potentiation. Here, six specific hypotheses are developed in light of additional mechanisms and evidence. Comparable potencies to ketamine for DM and DX are detailed for σ(1) (DX>DM>ketamine), NMDA PCP site (DX>ketamine>DM), and muscarinic (DX>ketamine>DM) receptors, 5HTT (DM>DX≫ketamine), and NMDA antagonist potentiation of μ receptor stimulation (DM>ketamine). Rapid acting antidepressant properties of DM include NMDA high-affinity site, NMDR-2A, and functional NMDR-2B receptor antagonism, σ(1) stimulation, putative mTOR activation (by σ(1) stimulation, μ potentiation, and 5HTT inhibition), putative AMPA receptor trafficking (by mTOR activation, PCP antagonism, σ(1) stimulation, μ potentiation, and 5HTT inhibition), and dendritogenesis, spinogenesis, synaptogenesis, and neuronal survival by NMDA antagonism and σ(1) and mTOR signaling. Those for dextrorphan include NMDA high-affinity site and NMDR-2A antagonism, σ(1) stimulation, putative mTOR activation (by σ(1) stimulation and ß adrenoreceptor stimulation), putative AMPA receptor trafficking (by mTOR activation, PCP antagonism, σ(1) stimulation, ß stimulation, and μ antagonism), and dendritogenesis, spinogenesis, synaptogenesis, and neuronal survival by NMDA antagonism and σ(1) and mTOR signaling. Conventional antidepressant properties for dextromethorphan and dextrorphan include 5HTT and norepinephrine transporter inhibition, σ(1) stimulation, NMDA and PCP antagonism, and possible serotonin 5HT1b/d receptor stimulation. Additional properties for

  20. Involvement of AMPA receptors in the antidepressant-like effects of dextromethorphan in mice.

    PubMed

    Nguyen, Linda; Matsumoto, Rae R

    2015-12-15

    Dextromethorphan (DM) is an antitussive with rapid acting antidepressant potential based on pharmacodynamic similarities to ketamine. Building upon our previous finding that DM produces antidepressant-like effects in the mouse forced swim test (FST), the present study aimed to establish the antidepressant-like actions of DM in the tail suspension test (TST), another well-established model predictive of antidepressant efficacy. Additionally, using the TST and FST, we investigated the role of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors in the antidepressant-like properties of DM because accumulating evidence suggests that AMPA receptors play an important role in the pathophysiology of depression and may contribute to the efficacy of antidepressant medications, including that of ketamine. We found that DM displays antidepressant-like effects in the TST similar to the conventional and fast acting antidepressants characterized by imipramine and ketamine, respectively. Moreover, decreasing the first-pass metabolism of DM by concomitant administration of quinidine (CYP2D6 inhibitor) potentiated antidepressant-like actions, implying DM itself has antidepressant efficacy. Finally, in both the TST and FST, pretreatment with the AMPA receptor antagonist NBQX (2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide) significantly attenuated the antidepressant-like behavior elicited by DM. Together, the data show that DM exerts antidepressant-like actions through AMPA receptors, further suggesting DM may act as a safe and effective fast acting antidepressant drug.

  1. Polymeric membrane sensors for the selective determination of dextromethorphan in pharmaceutical preparations.

    PubMed

    El-Naby, Eman H

    2008-01-01

    The construction and electrochemical response characteristics of poly(vinyl chloride) matrix ion-selective electrodes (ISEs) for dextromethorphan (DXM) hydrobromide are described. The membranes incorporate ion-association complexes of DXM with reineckate salt {[Cr(NH3)2(SCN)4]NH4} or phosphomolybdic acid [H3(PMo12O40)], as electroactive materials and dioctylphthalate or dibutylsebacate as a plasticizing solvent mediator. The sensors display a fast, stable and linear response with slopes of 54.4 to 59.5 mV/decade at pH 2.5-6.5 and a detection limit of 1.0 x 10(-6) M. Moreover, the sensors exhibit very good selectivity for DXM over opiate alkaloids, as well as organic and inorganic cations. The sensors proved to be useful for the determination of 5.0 x 10(-5)-1.0 x 10(-3) M DXM hydrobromide in pure as well as in dosage forms by direct potentiometry and standard addition methods. Determination of 5.0 x 10(-4) M DXM using the standard addition method and a sensor based on phosphomolybdate and dioctylphthalate shows an average recovery of 99.8% and a relative standard deviation (RSD) of 0.4%.

  2. Separation and determination of pseudoephedrine, dextromethorphan, diphenhydramine and chlorpheniramine in cold medicines by nonaqueous capillary electrophoresis.

    PubMed

    Dong, Yuming; Chen, Xiaofeng; Chen, Yonglei; Chen, Xingguo; Hu, Zhide

    2005-09-01

    An easy, rapid and simple nonaqueous capillary electrophoresis (NACE) method was developed for the identification and determination of four basic nitrogenous compounds, i.e. pseudoephedrine (PE), dextromethorphan (DXM), diphenhydramine (DHM) and chlorpheniramine (CLP). The most suitable running buffer was composed of 40 mM ammonium acetate, 10% acetonitrile (ACN) in methanol with a fused-silica capillary column (47 cm x 75 microm i.d.), 25 kV applied voltage and 25 degrees C capillary temperature. The calibration curves revealed linear relationships between the peak area for each analyte and its concentration (correlation coefficients: 0.9993 for PE, 0.9971 for DXM, 0.9991 for DHM, and 0.9995 for CLP, respectively). The relative standard deviations of the migration time and peak area of the four compounds were 0.37, 3.90, 0.73 and 0.68, and 2.80, 3.50, 1.60 and 3.70%, respectively. The method was successfully applied to determine the four compounds in five cold medicines, the recoveries of the four constituents ranging between 91 and 109%.

  3. Comparative Effects of Triflusal, S-Adenosylmethionine, and Dextromethorphan over Intestinal Ischemia/Reperfusion Injury

    PubMed Central

    Cámara-Lemarroy, Carlos R.; Guzmán-de la Garza, Francisco J.; Cordero-Pérez, Paula; Alarcón-Galván, Gabriela; Torres-Gonzalez, Liliana; Muñoz-Espinosa, Linda E.; Fernández-Garza, Nancy E.

    2011-01-01

    Ischemia/reperfusion (I/R) is a condition that stimulates an intense inflammatory response. No ideal treatment exists. Triflusal is an antiplatelet salicylate derivative with anti-inflammatory effects. S-adenosylmethionine is a metabolic precursor for glutathione, an endogenous antioxidant. Dextromethorphan is a low-affinity N-methyl-D-aspartate receptor inhibitor. There is evidence that these agents modulate some of the pathways involved in I/R physiopathology. Intestinal I/R was induced in rats by clamping the superior mesenteric artery for 60 minutes, followed by 60 minutes of reperfusion. Rats either received saline or the drugs studied. At the end of the procedure, serum concentrations of tumor necrosis factor-alpha (TNF-alpha), malonaldehyde (MDA), and total antioxidant capacity (TAC) were determined and intestinal morphology analyzed. I/R resulted in tissue damage, serum TNF-alpha and MDA elevations, and depletion of TAC. All drugs showed tissue protection. Only triflusal reduced TNF-alpha levels. All drugs lowered MDA levels, but only triflusal and S-adenosylmethionine maintained the serum TAC. PMID:22125445

  4. Therapeutic effects of add-on low-dose dextromethorphan plus valproic acid in bipolar disorder.

    PubMed

    Chen, Shiou-Lan; Lee, Sheng-Yu; Chang, Yun-Hsuan; Chen, Po-See; Lee, I-Hui; Wang, Tzu-Yun; Chen, Kao-Ching; Yang, Yen-Kuang; Hong, Jau-Shyong; Lu, Ru-Band

    2014-11-01

    Changes in inflammatory cytokines and dysfunction of the neurotrophic system are thought to be involved in the pathology of bipolar disorder (BP). We investigated whether inflammatory and neurotrophic factors were changed in BP. We also investigated whether treating BP with valproic acid (VPA) plus low-dose (30 or 60 mg/day) dextromethorphan (DM) is more effective than treating it with VPA only, and whether DM affects plasma cytokines and brain derived neurotrophic factor (BDNF) levels. In a 12-week, randomized, double-blind study, patients were randomly assigned to the VPA+DM30, VPA+DM60, or VPA+Placebo groups. The Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale (HDRS) were used to evaluate symptom severity, and ELISA to analyze plasma cytokine and BDNF levels. We recruited 309 patients with BP and 123 healthy controls. Before treatment, patients with BP had significantly higher plasma cytokine and lower plasma BDNF levels than did healthy controls. After treatment, HDRS and YMRS scores in each group showed significant improvement. Plasma cytokine levels tended to decline in all groups. Changes in plasma BDNF levels were significantly greater in the VPA+DM60 group than in the VPA+Placebo group. patients with BP have a certain degree of systemic inflammation and BDNF dysfunction. Treatment with VPA plus DM (60 mg/day) provided patients with BP significantly more neurotrophic benefit than did VPA treatment alone. Copyright © 2014 Elsevier B.V. and ECNP. All rights reserved.

  5. Fluorescent bovine serum albumin interacting with the antitussive quencher dextromethorphan: a spectroscopic insight.

    PubMed

    Durgannavar, Amar K; Patgar, Manjanath B; Nandibewoor, Sharanappa T; Chimatadar, Shivamurti A

    2016-05-01

    The interaction of dextromethorphan hydrobromide (DXM) with bovine serum albumin (BSA) is studied by using fluorescence spectra, UV-vis absorption, synchronous fluorescence spectra (SFS), 3D fluorescence spectra, Fourier transform infrared (FTIR) spectroscopy and circular dichroism under simulated physiological conditions. DXM effectively quenched the intrinsic fluorescence of BSA. Values of the binding constant, K(A), are 7.159 × 10(3), 9.398 × 10(3) and 16.101 × 10(3)  L/mol; the number of binding sites, n, and the corresponding thermodynamic parameters ΔG°, ΔH° and ΔS° between DXM and BSA were calculated at different temperatures. The interaction between DXM and BSA occurs through dynamic quenching and the effect of DXM on the conformation of BSA was analyzed using SFS. The average binding distance, r, between the donor (BSA) and acceptor (DXM) was determined based on Förster's theory. The results of fluorescence spectra, UV-vis absorption spectra and SFS show that the secondary structure of the protein has been changed in the presence of DXM. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Effects of dextromethorphan on glial cell function: proliferation, maturation, and protection from cytotoxic molecules.

    PubMed

    Lisak, Robert P; Nedelkoska, Liljana; Benjamins, Joyce A

    2014-05-01

    Dextromethorphan (DM), a sigma receptor agonist and NMDA receptor antagonist, protects neurons from glutamate excitotoxicity, hypoxia and ischemia, and inhibits microglial activation, but its effects on differentiation and protection of cells in the oligodendroglial lineage are unknown. It is important to protect oligodendroglia (OL) to prevent demyelination and preserve axons, and to protect oligodendroglial progenitors (OPC) to optimize myelination during development and remyelination following damage. Enriched glial cultures from newborn rat brain were used 1-2 days or 6-8 days after shakeoff for OPC or mature OL. DM had large effects on glial proliferation in less mature cultures in contrast to small variable effects in mature cultures; 1 μM DM stimulated proliferation of OPC by 4-fold, microglia (MG) by 2.5-fold and astroglia (AS) by 2-fold. In agreement with increased OPC proliferation, treatment of OPC with DM for 3 days increased the % of OPC relative to OL, with a smaller difference by 5 days, suggesting that maturation of OPC to OL was "catching up" by 5 days. DM at 2 and 20 μM protected both OL and OPC from killing by glutamate as well as NMDA, AMPA, quinolinic acid, staurosporine, and reactive oxygen species (ROS). DM did not protect against kynurenic acid, and only modestly against NO. These agents and DM were not toxic to AS or MG at the concentrations used. Thus, DM stimulates proliferation of OPC, and protects both OL and OPC against excitotoxic and inflammatory insults. Copyright © 2014 Wiley Periodicals, Inc.

  7. Evaluation of a [13C]-Dextromethorphan Breath Test to Assess CYP2D6 Phenotype

    PubMed Central

    Leeder, J. Steven; Pearce, Robin E.; Gaedigk, Andrea; Modak, Anil; Rosen, David I.

    2016-01-01

    A [13C]-dextromethorphan ([13C]-DM) breath test was evaluated to assess its feasibility as a rapid, phenotyping assay for CYP2D6 activity. [13C]-DM (0.5 mg/kg) was administered orally with water or potassium bicarbonate-sodium bicarbonate to 30 adult Caucasian volunteers (n = 1 each): CYP2D6 poor metabolizers (2 null alleles; PM-0) and extensive metabolizers with 1 (EM-1) or 2 functional alleles (EM-2). CYP2D6 phenotype was determined by 13CO2 enrichment measured by infrared spectrometry (delta-over-baseline [DOB] value) in expired breath samples collected before and up to 240 minutes after [13C]-DM ingestion and by 4-hour urinary metabolite ratio. The PM-0 group was readily distinguishable from either EM group by both the breath test and urinary metabolite ratio. Using a single point determination of phenotype at 40 minutes and defining PMs as subjects with a DOB ≤ 0.5, the sensitivity of the method was 100%; specificity was 95% with 95% accuracy and resulted in the misclassification of 1 EM-1 individual as a PM. Modification of the initial protocol (timing of potassium bicarbonate-sodium bicarbonate administration relative to dose) yielded comparable results, but there was a tendency toward increased DOB values. Although further development is required, these studies suggest that the [13C]-DM breath test offers promise as a rapid, minimally invasive phenotyping assay for CYP2D6 activity. PMID:18728242

  8. Analysis of Dextromethorphan and Dextrorphan in Skeletal Remains Following Decomposition in Different Microclimate Conditions.

    PubMed

    Unger, K A; Watterson, J H

    2016-10-01

    The effects of decomposition microclimate on the distribution of dextromethorphan (DXM) and dextrorphan (DXT) in skeletonized remains of rats acutely exposed to DXM were examined. Animals (n = 10) received DXM (75 mg/kg, i.p.), were euthanized 30 min post-dose and immediately allowed to decompose at either Site A (shaded forest microenvironment on a grass-covered soil substrate) or Site B (rocky substrate exposed to direct sunlight, 600 m from Site A). Ambient temperature and relative humidity were automatically recorded 3 cm above rats at each site. Skeletal elements (vertebral columns, ribs, pelvic girdles, femora, tibiae, humeri and scapulae) were harvested, and analyzed using microwave assisted extraction, microplate solid phase extraction, and GC/MS. Drug levels, expressed as mass-normalized response ratios, and the ratios of DXT and DXM levels were compared across bones and between microclimate sites. No significant differences in DXT levels or metabolite/parent ratios were observed between sites or across bones. Only femoral DXM levels differed significantly between microclimate sites. For pooled data, microclimate was not observed to significantly affect analyte levels, nor the ratio of levels of DXT and DXM. These data suggest that microclimate conditions do not influence DXM and metabolite distribution in skeletal remains. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Spectrophotometric Determination of Pipazethate HCl and Dextromethorphan HBr using Potassium Permanganate.

    PubMed

    Gouda, Ayman Abou El-Fetouh; El-Sheikh, Ragaa; El Shafey, Zeineb; Hossny, Nagda; El-Azzazy, Rham

    2008-12-01

    Rapid, simple and sensitive validated spectrophotometric methods have been described for the assay of pipazethate HCl (PiCl) and dextromethorphan HBr (DEX) either in pure form or in pharmaceutical formulations. The proposed methods were based on the oxidation of the studied drugs by a known excess of potassium permanganate in acidic medium and estimating the unreacted permanganate with amaranth dye (method A), acid orange II (method B), indigocarmine (method C) and methylene blue (method D), in the same acid medium at a suitable λmax=521, 485, 610 and 664 nm, respectively. Beer's law is obeyed in the concentration range of 2.0-16 and 2.0-15 μg mL(-1) for PiCl and DEX, respectively with correlation coefficient (n=6) ≥ 0.9993. The apparent molar absorptivity and sandell sensitivity values are in the range 1.062-1.484 × 10(4), 3.35-4.51 × 10(4) L mol(-1) cm(-1) and 29.36-41.03, 8.21-11.06 ng cm(-2) for PiCl and DEX, respectively. Different variables affecting the reaction were studied and optimized. The proposed methods were applied successfully to the determination of the examined drugs either in a pure or pharmaceutical dosage forms with good accuracy and precision. No interferences were observed from excipients and the results obtained were in good agreement with those obtained using the official methods.

  10. Normal-phase LC method for simultaneous analysis of pseudophedrine hydrochloride, dextromethorphan hydrobromide, chlorpheniramine maleate, and paracetamol in tablet formulations.

    PubMed

    Al-Rimawi, Fuad

    2010-04-01

    A simple, precise, and accurate method is developed and validated for the analysis of pseudophedrine hydrochloride, dextromethorphan hydrobromide, chlorpheniramine maleate, and paracetamol in tablet formulations. The method has shown adequate separation of the four ingredients from each other. Separation was achieved on a silica column (5 μm, 125 × 4.6 mm inner diameter) using a mobile phase consisting of methanol/ammonium dihydrogen phosphate buffer (90:10, v/v) at a flow rate of 1.0 ml/min and UV detection at 220 nm. This new method is validated in accordance with USP requirements for new methods for assay determination, which include accuracy, precision, selectivity, linearity and range, robustness and ruggedness. The current method demonstrates good linearity over the range of 0.15-0.45 mg/ml of pseudophedrine hydrochloride with r (2) of 0.996, and in the range of 0.075-0.225 mg/ml of dextromethorphan hydrobromide with r (2) of 0.992, and in the range of 0.01-0.03 mg/ml of chlorpheniramine maleate with r (2) of 0.994, and in the range of 0.25-0.75 mg/ml of paracetamol with r (2) of 0.991. The average recovery of the method is 99.7%, 98.6%, 98.1%, and 99.2% for pseudophedrine hydrochloride, dextromethorphan hydrobromide, chlorpheniramine maleate, and paracetamol, respectively. The degree of reproducibility of the results obtained as a result of small deliberate variations in the method parameters and by changing analytical operator has proven that the method is robust and rugged.

  11. Multi-Modal Preemptive Analgesia With Pregabalin, Acetaminophen, Naproxen, and Dextromethorphan in Radical Neck Dissection Surgery: A Randomized Clinical Trial

    PubMed Central

    Amiri, Hamid Reza; Mirzaei, Mojtaba; Beig Mohammadi, Mohammad Taghi; Tavakoli, Farhad

    2016-01-01

    Background Preemptive analgesia may be considered as a method not only to alleviate postoperative pain but also to decrease analgesic consumption. Different regimens are suggested, but there is currently no standard. Objectives The aim was to measure the efficacy of preemptive analgesia with pregabalin, acetaminophen, naproxen, and dextromethorphan in radical neck dissection surgery for reducing the intensity of pain and morphine consumption. Patients and Methods This study was conducted as a randomized double-blind clinical trial. Eighty adult patients (18 to 60 years of age) under the American society of anesthesiologists (ASA) physical status I and II undergoing elective radical neck dissection were enrolled. Patients were randomized into two groups of 40 with a simple randomization method. The case group received a combination of 15 mg/kg acetaminophen, 2.5 mg/kg pregabalin, 7 mg/kg naproxen, and 0.3 mg/kg dextromethorphan administered orally one hour prior to surgery. Postoperative pain was assessed with the universal pain assessment tool (UPAT) at 0, 2, 4, 6, 12, and 24 hours after surgery. Subjects received morphine based on postoperative pain control protocol. Total administered morphine doses were noted. Results Postoperative pain rates at 0, 2, 4, 6, 12, and 24 hours after surgery were significantly lower for the case group than the control group (P values = 0.014, 0.003, 0.00, 0.00, and 0.00, respectively). Total morphine doses for the preemptive analgesia group were 45% lower than those of the other group. Side effects were similar for both groups. Conclusions A single preoperative oral dose of pregabalin, acetaminophen, dextromethorphan, and naproxen one hour before surgery is an effective method for reducing postoperative pain and morphine consumption in patients undergoing radical neck dissection. PMID:27843771

  12. High-performance liquid chromatographic analysis of dextromethorphan, guaifenesin and benzoate in a cough syrup for stability testing.

    PubMed

    Galli, V; Barbas, C

    2004-09-10

    A method has been developed for the analysis of a cough syrup containing dextromethorphan, guaifenesin, benzoic acid, saccharin and other components. Forced degradation was also studied to demonstrate that the method could be employed during a stability study of the syrup. Final conditions were phosphate buffer (25 mM, pH 2.8) with triethylamine (TEA)-acetonitrile (75:25, v/v). In such conditions, all the actives, excipients and degradation products were baseline resolved in less than 14 min, and different wavelengths were used for the different analytes and related compounds.

  13. Comparative efficacy and tolerability of pholcodine and dextromethorphan in the management of patients with acute, non-productive cough : a randomized, double-blind, multicenter study.

    PubMed

    Equinozzi, Roberto; Robuschi, Maria

    2006-01-01

    The aim of this study was to compare the efficacy and tolerability of pholcodine with that of dextromethorphan, one of the most used cough sedative products, in patients with acute, non-productive cough. 129 adults with a diagnosis of acute, frequent, non-productive cough participated in a randomized, double-blind, parallel-group, multicenter trial. Medications were in a syrup formulation and were taken orally three times daily for 3 days. The efficacy endpoints were the change from baseline in the daytime and night-time cough frequency on 5-point scales at day 3, and cough intensity. A reduction of 1.4 and 1.3 points in the mean daytime cough frequency at day 3 was seen in the pholcodine and dextromethorphan groups, respectively, in the per-protocol population. The reduction in mean night-time cough was 1.3 for both groups. Cough intensity reduction was 0.7 for pholcodine and 0.8 for dextromethorphan. These findings indicate that the efficacy of a 3-day course of pholcodine is similar to that of dextromethorphan in the treatment of adult patients with acute, non-productive cough. Both medications were well tolerated.

  14. Acute cognitive effects of high doses of dextromethorphan relative to triazolam in humans

    PubMed Central

    Carter, Lawrence P.; Reissig, Chad J.; Johnson, Matthew W.; Klinedinst, Margaret A.; Griffiths, Roland R.

    2012-01-01

    BACKGROUND Although concerns surrounding high-dose dextromethorphan (DXM) abuse have recently increased, few studies have examined the acute cognitive effects of high doses of DXM. The aim of this study was to compare the cognitive effects of DXM with those of triazolam and placebo. METHODS Single, acute, oral doses of DXM (100, 200, 300, 400, 500, 600, 700, 800 mg/70 kg), triazolam (0.25, 0.5 mg /70 kg), and placebo were administered p.o. to twelve healthy volunteers with histories of hallucinogen use, under double-blind conditions, using an ascending dose run-up design. Effects on cognitive performance were examined at baseline and after drug administration for up to 6 hours. RESULTS Both triazolam and DXM produced acute impairments in attention, working memory, episodic memory, and metacognition. Impairments observed following doses of 100-300 mg/70 kg DXM were generally smaller in magnitude than those observed after 0.5 mg/70 kg triazolam. Doses of DXM that impaired performance to the same extent as triazolam were in excess of 10-30 times the therapeutic dose of DXM. CONCLUSION The magnitude of the doses required for these effects and the absence of effects on some tasks within the 100-300 mg/70 kg dose range of DXM, speak to the relatively broad therapeutic window of over-the-counter DXM preparations when used appropriately. However, the administration of supratherapeutic doses of DXM resulted in acute cognitive impairments on all tasks that were examined. These findings are likely relevant to cases of high-dose DXM abuse. PMID:22989498

  15. Effects of dextromethorphan and oxycodone on treatment of neuropathic pain in mice.

    PubMed

    Yang, Pao-Pao; Yeh, Geng-Chang; Huang, Eagle Yi-Kung; Law, Ping-Yee; Loh, Horace H; Tao, Pao-Luh

    2015-09-22

    Neuropathic pain is a very troublesome and difficult pain to treat. Although opioids are the best analgesics for cancer and surgical pain in clinic, only oxycodone among opioids shows better efficacy to alleviate neuropathic pain. However, many side effects associated with the use of oxycodone render the continued use of it in neuropathic pain treatment undesirable. Hence, we explored whether dextromethorphan (DM, a known N-methyl-D-aspartate receptor antagonist with neuroprotective properties) could potentiate the anti-allodynic effect of oxycodone and underlying mechanisms regarding to glial cells (astrocytes and microglia) activation and proinflammatory cytokines release in a spinal nerve injury (SNL) mice model. Oxycodone produced a dose-dependent anti-allodynic effect. Co-administration of DM at a dose of 10 mg/kg (i.p.) (DM10) which had no anti-allodynic effect by itself enhanced the acute oxycodone (1 mg/kg, s.c.) effect. When the chronic anti-allodynic effects were examined, co-administration of DM10 also significantly enhanced the oxycodone effect at 3 mg/kg. Furthermore, oxycodone decreased SNL-induced activation of glial cells (astrocytes and microglia) and plasma levels of proinflammatory cytokines (IL-6, IL-1β and TNF-α). Co-administration of DM10 potentiated these effects of oxycodone. The combined use of DM with oxycodone may have therapeutic potential for decreasing the effective dose of oxycodone on the treatment of neuropathic pain. Attenuation of the glial activation and proinflammatory cytokines in the spinal cord may be important mechanisms for these effects of DM.

  16. A COMBINED EFFECT OF DEXTROMETHORPHAN AND MELATONIN ON NEUROPATHIC PAIN BEHAVIOR IN RATS

    PubMed Central

    Wang, Shuxing; Zhang, Lin; Lim, Grewo; Sung, Backil; Tian, Yinghong; Chou, Chiu-Wen; Hernstadt, Hayley; Rusanescu, Gabriel; Ma, Yuxin; Mao, Jianren

    2009-01-01

    Previous study has shown that administration of melatonin into the anterior cingulate cortex contralateral to peripheral nerve injury prevented exacerbation of mechanical allodynia with a concurrent improvement of depression-like behavior in Wistar-Kyoto (WKY) rats, a genetic variation of Wistar rats. In the present study, we examined the effect of the individual versus combined treatment of melatonin and/or dextromethorphan (DM), a clinically available N-methyl-D-aspartate (NMDA) receptor antagonist, on pain behaviors in WKY rats with chronic constriction sciatic nerve injury (CCI). Pain behaviors (thermal hyperalgesia and mechanical allodynia) were established at one week after CCI. WKY rats were then treated intraperitoneally with various doses of melatonin, DM or their combination once daily for the following week. At the end of this one-week treatment, behavioral tests were repeated in these same rats. While DM alone was effective in reducing thermal hyperalgesia at three tested doses (15, 30 or 60 mg/kg), it reduced mechanical allodynia only at high doses (30 or 60 mg/kg). By comparison, administration of melatonin alone was effective in reducing thermal hyperalgesia only at the highest dose (120 mg/kg, but not 30 or 60 mg/kg) tested in this experiment. Melatonin alone failed to reverse allodynia at all three tested doses (30, 60 and 120 mg/kg). However, the combined intraperitoneal administration of melatonin (30 mg/kg) and DM (15 mg/kg) effectively reversed both thermal hyperalgesia and mechanical allodynia although each individual dose alone did not reduce pain behaviors. These results suggest that a combination of melatonin with a clinically available NMDA receptor antagonist might be more effective than either drug alone for the treatment of neuropathic pain. PMID:19595681

  17. Inflammation in Patients with Schizophrenia: the Therapeutic Benefits of Risperidone Plus Add-On Dextromethorphan

    PubMed Central

    Chen, Shiou-Lan; Lee, Sheng-Yu; Chang, Yun-Hsuan; Chen, Shih-Heng; Chu, Chun-Hsieh; Tzeng, Nian-Sheng; Lee, I-Hui; Chen, Po-See; Yeh, Tzung Lieh; Huang, San-Yuan; Yang, Yen-Kuang; Lu, Ru-Band; Hong, Jau-Shyong

    2013-01-01

    Objectives Increasing evidence suggests that inflammation contributes to the etiology and progression of schizophrenia. Molecules that initiate inflammation, such as virus- and toxin-induced cytokines, are implicated in neuronal degeneration and schizophrenia-like behavior. Using therapeutic agents with anti-inflammatory or neurotrophic effects may be beneficial for treating schizophrenia. Methods One hundred healthy controls and 95 Han Chinese patients with schizophrenia were tested in this double-blind study. Their PANSS scores, plasma interleukin (IL)-1β, TNF-α and brain-derived neurotrophic factor (BDNF) levels were measured before and after pharmacological treatment. Results Pretreatment, plasma levels of IL-1β and TNF-α were significantly higher in patients with schizophrenia than in controls, but plasma BDNF levels were significantly lower. Patients were treated with the atypical antipsychotic risperidone (Risp) only or with Risp+add-on dextromethorphan (DM). PANSS scores and plasma IL-1β levels significantly decreased, but plasma TNF-α and BDNF levels significantly increased after 11 weeks of Risp treatment. Patients in the Risp+DM group showed a greater and earlier reduction of symptoms than did those in the Risp-only group. Moreover, Risp+DM treatment attenuated Risp-induced plasma increases in TNF-α. Conclusion Patients with schizophrenia had a high level of peripheral inflammation and a low level of peripheral BDNF. Long-term Risp treatment attenuated inflammation and potentiated the neurotrophic function but also produced a certain degree of toxicity. Risp+DM was more beneficial and less toxic than Risp-only treatment. PMID:22730040

  18. Pharmacokinetic profile of dextromethorphan hydrobromide in a syrup formulation in children and adolescents.

    PubMed

    Guenin, Eric; Armogida, Marianna; Riff, Dennis

    2014-09-01

    Dextromethorphan hydrobromide (DM) is a widely used antitussive. This study determined, for the first time, the basic pharmacokinetic profile of DM and its active metabolite, dextrorphan (DP) in children and adolescents. Thirty-eight male and female subjects at risk for developing an upper respiratory tract infection (URTI), or symptomatic with cough due to URTI, were enrolled in this single-dose, open-label study: ages 2-5 years (Group A, n = 8), 6-11 years (Group B, n = 17), 12-17 years (Group C, n = 13). Subjects were genotyped for cytochrome P450 (CYP) 2D6 polymorphisms and characterized as poor (PM) or non-poor metabolizers (non-PM). Groups A and B were dosed using an age-weight dosing schedule (DM range 7.5-24.75 mg); a 30-mg dose was used for Group C. Average exposures to total DP increased as age group increased, and average exposure to DM was highest in the adolescent group. One subject in that group was a PM. The terminal half-life (t ½) values were longer in the adolescent group due in part to the single PM subject. No relationship between body weight and pharmacokinetic parameters was noted. This is the first evaluation of the pharmacokinetic characteristics of DM in children and adolescents. A single dose of DM in this population was safe, and well tolerated at all doses tested. The data are used to model and compare pediatric DM exposures with those of adults.

  19. Dextromethorphan upregulates osteoblast and osteoclast activity but does not attenuate ovariectomy-induced osteoporosis.

    PubMed

    Wu, Jia-Lin; Tsai, Wei-Yuan; Chen, Jian-Horng; Wong, Chih-Shung

    2017-03-15

    Study on the in vivo regulatory role of glutamate in osteoblast (OB) and osteoclast (OC) differentiation is less advanced. The present study investigated the effect of dextromethorphan (DXM), an N-methyl-d-aspartate receptors (NMDARs) antagonist, on osteoporosis development. In order to examine the role of glutamate in bone metabolism, ovariectomized (Ovx) female Wistar rats were injected three times per week for 8weeks with either saline, or 15μg/kg of β-estrodiol, or DXM (40mg/kg) intraperitoneally. Serum samples were collected every two weeks for measuring osteocalcin and C-terminal telopeptide of type I collagen (CTX-1) level. Rats were then sacrificed at week 8 and the femurs harvested for micro-CT scanning and mechanical strength. In saline-treated group, osteocalcin level significantly lower than that of sham-operated rats at 8weeks after operation, while CTX-1 levels were not affected. Estrogen treatment, as a positive control, partially inhibited the Ovx-induced reduction of osteocalcin serum level. DXM injection prevented the Ovx-induced reduction of osteocalcin expression and significantly upregulated CTX-1 expression. The micro-CT scan showed that the bone volume density decreased significantly in DXM treated rats compared to the sham-operated rats. In the mechanical strength assay, the maximum failure load for DXM treatment was significantly lower than the other groups. Treatment with DXM upregulated OB and OC markers in Ovx rats, however with a greater effect on the OC marker, and had no significant benefit on bone volume density or bone strength. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Lack of effect of chronic dextromethorphan on experimental pain tolerance in methadone-maintained patients

    PubMed Central

    Compton, Peggy A.; Ling, Walter; Torrington, Matt A.

    2014-01-01

    Good evidence exists to suggest that individuals on opioid maintenance for the treatment of addiction (i.e. methadone) are less tolerant of experimental pain than are matched controls or ex-opioid addicts, a phenomenon theorized to reflect opioid-induced hyperalgesia (OIH). Agonist activity at the excitatory ionotropic N-methyl-D-aspartate (NMDA) receptor on dorsal horn neurons has been implicated in the development of both OIH and its putative expression at the clinical level—opioid tolerance. The aim of this study was to evaluate the potential utility of the NMDA-receptor antagonist, dextromethorphan (DEX), to reverse or treat OIH in methadone-maintenance (MM) patients. Utilizing a clinical trial design and double-blind conditions, changes in pain threshold and tolerance [cold pressor (CP) and electrical stimulation (ES)] following a 5-week trial of DEX (titrated to 480 mg/day) in comparison with placebo was evaluated in a well-characterized sample of MM patients. The sample (n = 40) was 53% male and ethnically diverse (53% Latino, 28% African American, 10% White, 9% other), with a mean age of 48.0 years (SD = 6.97). Based on t-test analyses, no difference was found between groups on CP pain threshold, CP pain tolerance, ES pain threshold or ES pain tolerance, both pre- and postmedication. Notably, DEX-related changes significantly differed by gender, with women tending to show diminished tolerance for pain with DEX therapy. These results support that chronic high-dose NMDA antagonism does not improve tolerance for pain in MM patients, although a gender effect on DEX response is suggested. PMID:18507735

  1. Determination of Dextromethorphan in Oral Fluid by LC-MS-MS.

    PubMed

    Amaratunga, Piyadarsha; Clothier, Morgan; Lorenz Lemberg, Bridget; Lemberg, Dave

    2016-06-01

    Dextromethorphan (DXM) is an antitussive drug found in commonly used nonprescription cold and cough medications. At low doses, DXM is a safe drug that does not produce adverse reactions. However, abuse of DXM has been reported among adolescents and young adults using the drug at higher doses. DXM is not a scheduled drug in the USA, and the primary reason for its abuse is the ease of availability. DXM is available to purchase in the form of over-the-counter cough medications, such as Robitussin(®) and Coricidin(®), or it can be purchased over the Internet in the form of a powder. In this research work, we developed an LC-MS-MS method that can quantify DXM and dextrorphan (DXO) in oral fluid in a high-throughput toxicology laboratory setting. The developed method was validated according to the Scientific Working Group for Forensic Toxicology guidelines. The linear dynamic range was 5-100 ng/mL with a lowest limit of quantitation (LLOQ) of 5.0 ng/mL for DXM and DXO. Overall, the results of the accuracy and the precision values were within the acceptance criteria for both drugs. In addition, selectivity, matrix effect and recovery were calculated for the LC-MS-MS method. Authentic samples (n = 59) were tested to evaluate the applicability of the method. Thirty samples were found to be positive for DXM and DXO and two samples were found to be positive for DXM only. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. Intravenous dextromethorphan/quinidine inhibits activity of dura-sensitive spinal trigeminal neurons in rats.

    PubMed

    Sokolov, A Y; Lyubashina, O A; Berkovich, R R; Panteleev, S S

    2015-09-01

    Migraine is a chronic neurological disorder characterized by episodes of throbbing headaches. Practically all medications currently used in migraine prophylaxis have a number of substantial disadvantages and use limitations. Therefore, the further search for principally new prophylactic antimigraine agents remains an important task. The objective of our study was to evaluate the effects of a fixed combination of dextromethorphan hydrobromide and quinidine sulphate (DM/Q) on activity of the spinal trigeminal neurons in an electrophysiological model of trigemino-durovascular nociception. The study was performed in 15 male Wistar rats, which were anaesthetized with urethane/α-chloralose and paralysed using pipecuronium bromide. The effects of cumulative intravenous infusions of DM/Q (three steps performed 30 min apart, 15/7.5 mg/kg of DM/Q in 0.5 mL of isotonic saline per step) on ongoing and dural electrical stimulation-induced neuronal activities were tested in a group of eight rats over 90 min. Other seven animals received cumulative infusion of equal volumes of saline and served as control. Cumulative administration of DM/Q produced steady suppression of both the ongoing activity of the spinal trigeminal neurons and their responses to electrical stimulation of the dura mater. It is evident that the observed DM/Q-induced suppression of trigeminal neuron excitability can lead to a reduction in nociceptive transmission from meninges to higher centres of the brain. Since the same mechanism is believed to underlie the pharmacodynamics of many well-known antimigraine drugs, results of the present study enable us to anticipate the potential efficacy of DM/Q in migraine. © 2014 European Pain Federation - EFIC®

  3. The involvement of dorsal hippocampus in dextromethorphan-induced state-dependent learning in mice.

    PubMed

    Zarrindast, Mohammad-Reza; Ownegh, Vahid; Rezayof, Ameneh; Ownegh, Farid

    2014-01-01

    In an effort to understand the effect of dextromethorphan (DM; 3-methoxy-17-methylmorphinan), a noncompetitive antagonist of the N-methyl-d-aspartate (NMDA) receptors on memory retrieval, male NMRI mice received intraperitoneal (i.p.) or intra-CA1 injection of this drug before or after training and before testing in passive avoidance task. Pre-training i.p. (20mg/kg) or intra-CA1 (0.5 and 1 μg/mouse) administration of DM induced amnesia in a dose-dependent manner. Post-training i.p. (10 and 20mg/kg) or intra-CA administration of DM (0.5 and 1 μg/mouse) however, did not affect the memory retrieval. Moreover, memory retrieval was impaired in animals receiving either i.p. (20mg/kg) or intra-CA1 administration of DM (0.5 and 1 μg/mouse) prior to testing, suggesting the DM-induced amnesia. Interestingly, the amnestic effect of pre-training i.p. (20mg/kg) or intra-CA1 administration of DM (1 μg/mouse) was restored in mice receiving pre-test i.p. (5 and 10mg/kg) or intra-CA1 (0.25 and 0.5 μg/mouse) administration of the drug, indicating DM-induced state-dependent learning. Taken together, it can be concluded that DM administration impairs memory retrieval in a dose- and time-dependent manner. Moreover, DM can induce state-dependent learning. Dorsal hippocampus appears to play an important role upon DM influence of learning and memory processes. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. High doses of dextromethorphan, an NMDA antagonist, produce effects similar to classic hallucinogens

    PubMed Central

    Carter, Lawrence P.; Johnson, Matthew W.; Mintzer, Miriam Z.; Klinedinst, Margaret A.; Griffiths, Roland R.

    2013-01-01

    Rationale Although reports of dextromethorphan (DXM) abuse have increased recently, few studies have examined the effects of high doses of DXM. Objective This study in humans evaluated the effects of supratherapeutic doses of DXM and triazolam. Methods Single, acute, oral doses of DXM (100, 200, 300, 400, 500, 600, 700, 800 mg/70 kg), triazolam (0.25, 0.5 mg/70kg), and placebo were administered to twelve healthy volunteers with histories of hallucinogen use, under double-blind conditions, using an ascending dose run-up design. Subjective, behavioral, and physiological effects were assessed repeatedly after drug administration for 6 hours. Results Triazolam produced dose-related increases in subject-rated sedation, observer-rated sedation, and behavioral impairment. DXM produced a profile of dose-related physiological and subjective effects differing from triazolam. DXM effects included increases in blood pressure, heart rate, and emesis, increases in observer-rated effects typical of classic hallucinogens (e.g. distance from reality, visual effects with eyes open and closed, joy, anxiety), and participant ratings of stimulation (e.g. jittery, nervous), somatic effects (e.g. tingling, headache), perceptual changes, end-of-session drug liking, and mystical-type experience. After 400 mg/70kg DXM, 11 of 12 participants indicated on a pharmacological class questionnaire that they thought they had received a classic hallucinogen (e.g. psilocybin). Drug effects resolved without significant adverse effects by the end of the session. In a 1-month follow up volunteers attributed increased spirituality and positive changes in attitudes, moods, and behavior to the session experiences. Conclusions High doses of DXM produced effects distinct from triazolam and had characteristics that were similar to the classic hallucinogen psilocybin. PMID:22526529

  5. High doses of dextromethorphan, an NMDA antagonist, produce effects similar to classic hallucinogens.

    PubMed

    Reissig, Chad J; Carter, Lawrence P; Johnson, Matthew W; Mintzer, Miriam Z; Klinedinst, Margaret A; Griffiths, Roland R

    2012-09-01

    Although reports of dextromethorphan (DXM) abuse have increased recently, few studies have examined the effects of high doses of DXM. This study in humans evaluated the effects of supratherapeutic doses of DXM and triazolam. Single, acute oral doses of DXM (100, 200, 300, 400, 500, 600, 700, and 800 mg/70 kg), triazolam (0.25 and 0.5 mg/70 kg), and placebo were administered to 12 healthy volunteers with histories of hallucinogen use, under double-blind conditions, using an ascending dose run-up design. Subjective, behavioral, and physiological effects were assessed repeatedly after drug administration for 6 h. Triazolam produced dose-related increases in subject-rated sedation, observer-rated sedation, and behavioral impairment. DXM produced a profile of dose-related physiological and subjective effects differing from triazolam. DXM effects included increases in blood pressure, heart rate, and emesis; increases in observer-rated effects typical of classic hallucinogens (e.g., distance from reality, visual effects with eyes open and closed, joy, anxiety); and participant ratings of stimulation (e.g., jittery, nervous), somatic effects (e.g., tingling, headache), perceptual changes, end-of-session drug liking, and mystical-type experience. After 400 mg/70 kg DXM, 11 of 12 participants indicated on a pharmacological class questionnaire that they thought they had received a classic hallucinogen (e.g., psilocybin). Drug effects resolved without significant adverse effects by the end of the session. In a 1-month follow-up, volunteers attributed increased spirituality and positive changes in attitudes, moods, and behavior to the session experiences. High doses of DXM produced effects distinct from triazolam and had characteristics that were similar to the classic hallucinogen psilocybin.

  6. Inflammation in patients with schizophrenia: the therapeutic benefits of risperidone plus add-on dextromethorphan.

    PubMed

    Chen, Shiou-Lan; Lee, Sheng-Yu; Chang, Yun-Hsuan; Chen, Shih-Heng; Chu, Chun-Hsieh; Tzeng, Nian-Sheng; Lee, I-Hui; Chen, Po-See; Yeh, Tzung Lieh; Huang, San-Yuan; Yang, Yen-Kuang; Lu, Ru-Band; Hong, Jau-Shyong

    2012-09-01

    Increasing evidence suggests that inflammation contributes to the etiology and progression of schizophrenia. Molecules that initiate inflammation, such as virus- and toxin-induced cytokines, are implicated in neuronal degeneration and schizophrenia-like behavior. Using therapeutic agents with anti-inflammatory or neurotrophic effects may be beneficial for treating schizophrenia. One hundred healthy controls and 95 Han Chinese patients with schizophrenia were tested in this double-blind study. Their PANSS scores, plasma interleukin (IL)-1β, tumor necrosis factor-α (TNF-α) and brain-derived neurotrophic factor (BDNF) levels were measured before and after pharmacological treatment. Pretreatment, plasma levels of IL-1β and TNF-α were significantly higher in patients with schizophrenia than in controls, but plasma BDNF levels were significantly lower. Patients were treated with the atypical antipsychotic risperidone (Risp) only or with Risp+ dextromethorphan (DM). PANSS scores and plasma IL-1β levels significantly decreased, but plasma TNF-α and BDNF levels significantly increased after 11 weeks of Risp treatment. Patients in the Risp+ DM group showed a greater and earlier reduction of symptoms than did those in the Risp-only group. Moreover, Risp+ DM treatment attenuated Risp-induced plasma increases in TNF-α. Patients with schizophrenia had a high level of peripheral inflammation and a low level of peripheral BDNF. Long-term Risp treatment attenuated inflammation and potentiated the neurotrophic function but also produced a certain degree of toxicity. Risp+ DM was more beneficial and less toxic than Risp-only treatment. Protocol Record: HR-93-50; NCT01189006; URL: http://www.clinicaltrials.gov.

  7. Simultaneous determination of pseudoephdrine, pheniramine, guaifenisin, pyrilamine, chlorpheniramine and dextromethorphan in cough and cold medicines by high performance liquid chromatography.

    PubMed

    Louhaichi, M R; Jebali, S; Loueslati, M H; Adhoum, N; Monser, L

    2009-05-15

    A new simple, rapid and sensitive liquid chromatographic method has been developed and validated for the simultaneous determination of pseudoephdrine, pheniramine, guaifenisin, pyrilamine, chlorpheniramine and dextromethorphan in cough and cold pharmaceuticals. The separation of these compounds was achieved within 13 min on a Kromasil C18 column using an isocratic mobile phase consisting of methanol-dihydrogenphosphate buffer at pH 3 (45:55, v/v). The analysis was performed at a flow rate of 1 mL min(-1) and at a detection wavelength of 220 nm. The selectivity, linearity of calibration, accuracy, within and between-days precision and recovery were examined as parts of the method validation. The concentration-response relationship was linear over a concentration range of 5-50 microg mL(-1) for pseudoephdrine, pheniramine, chlorpheniramine and 50-600 microg mL(-1) for guaifenisin, pyrilamine, dextromethorphan, methylparaben and sodium benzoate with correlation coefficients better than 0.998. The standard deviations of the intraday and interday were all less than 2%. The proposed liquid chromatographic method was successfully applied for the routine analysis of these compounds in different cough and cold pharmaceutical preparations such as syrups, capsules, tablets and sachets. The presence of preservatives (sodium benzoate and methylparaben) and other excipients did not show any significant interference on the determination of these compounds.

  8. Effect of abiraterone acetate plus prednisone on the pharmacokinetics of dextromethorphan and theophylline in patients with metastatic castration-resistant prostate cancer.

    PubMed

    Chi, K N; Tolcher, A; Lee, P; Rosen, P J; Kollmannsberger, C K; Papadopoulos, K P; Patnaik, A; Molina, A; Jiao, J; Pankras, C; Kaiser, B; Bernard, A; Tran, N; Acharya, M

    2013-01-01

    To assess the effect of abiraterone acetate plus prednisone on the pharmacokinetics of dextromethorphan HBr (CYP2D6 substrate) and theophylline (CYP1A2 substrate) in patients with metastatic castration-resistant prostate cancer (mCRPC). Men with progressive metastatic mCRPC who failed gonadotropin-releasing hormone therapy and ≥1 lines of chemotherapy were enrolled. Patients received two doses of dextromethorphan HBr-30 mg (n = 18; group A) or theophylline-100 mg (n = 16; group B) under fasting conditions; one dose on cycle 1, day -8, and the other dose on cycle 1, day 8. Only patients with extensive CYP2D6 metabolizing status were assigned to group A. All patients received continuous daily oral abiraterone acetate (1,000 mg) plus prednisone (10 mg) starting on cycle 1, day 1. Coadministration of abiraterone acetate plus prednisone increased the systemic exposure of dextromethorphan by approximately 100%. Ratios of geometric means for maximum plasma concentration (C(max)) (275.36%) and area under plasma concentration-time curves from time 0 to 24 h (AUC(24h)) (268.14%) of dextromethorphan were outside the bioequivalence limit. The pharmacokinetics of theophylline was unaltered following coadministration of abiraterone acetate plus prednisone. Ratios of geometric means [C(max); 102.36% and AUC(24h); 108.03%] of theophylline exposure parameters were within the bioequivalence limit. The safety profile of abiraterone acetate was consistent with reported toxicities. Abiraterone acetate plus prednisone increased the exposure of dextromethorphan, suggesting a need for caution when coadministrating with known CYP2D6 substrates. The pharmacokinetics of theophylline was unaffected when coadministered with abiraterone acetate plus prednisone.

  9. Anti-dyskinetic mechanisms of amantadine and dextromethorphan in the 6-OHDA rat model of Parkinson's disease: role of NMDA vs. 5-HT1A receptors.

    PubMed

    Paquette, Melanie A; Martinez, Alex A; Macheda, Teresa; Meshul, Charles K; Johnson, Steven W; Berger, S Paul; Giuffrida, Andrea

    2012-11-01

    Amantadine and dextromethorphan suppress levodopa (L-DOPA)-induced dyskinesia (LID) in patients with Parkinson's disease (PD) and abnormal involuntary movements (AIMs) in the unilateral 6-hydroxydopamine (6-OHDA) rat model. These effects have been attributed to N-methyl-d-aspartate (NMDA) antagonism. However, amantadine and dextromethorphan are also thought to block serotonin (5-HT) uptake and cause 5-HT overflow, leading to stimulation of 5-HT(1A) receptors, which has been shown to reduce LID. We undertook a study in 6-OHDA rats to determine whether the anti-dyskinetic effects of these two compounds are mediated by NMDA antagonism and/or 5-HT(1A) agonism. In addition, we assessed the sensorimotor effects of these drugs using the Vibrissae-Stimulated Forelimb Placement and Cylinder tests. Our data show that the AIM-suppressing effect of amantadine was not affected by the 5-HT(1A) antagonist WAY-100635, but was partially reversed by the NMDA agonist d-cycloserine. Conversely, the AIM-suppressing effect of dextromethorphan was prevented by WAY-100635 but not by d-cycloserine. Neither amantadine nor dextromethorphan affected the therapeutic effects of L-DOPA in sensorimotor tests. We conclude that the anti-dyskinetic effect of amantadine is partially dependent on NMDA antagonism, while dextromethorphan suppresses AIMs via indirect 5-HT(1A) agonism. Combined with previous work from our group, our results support the investigation of 5-HT(1A) agonists as pharmacotherapies for LID in PD patients. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  10. Characterization of cytochrome P-450 2D1 activity in rat brain: high-affinity kinetics for dextromethorphan.

    PubMed

    Tyndale, R F; Li, Y; Li, N Y; Messina, E; Miksys, S; Sellers, E M

    1999-08-01

    We investigated the enzymatic function, stability, and regional distribution of rat brain cytochrome P-450 (CYP) 2D1 activity. CYP2D1 is the homolog of human CYP2D6, a genetically variable enzyme that activates or inactivates many clinical drugs acting on the central nervous system (e.g., antidepressants, monoamine oxidase inhibitors, serotonin uptake inhibitors, and neuroleptics), drugs of abuse (e.g., amphetamine and codeine), neurotoxins (e.g., 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, 1,2,3, 4-tetrahydroquinoline), and endogenous neurochemicals (e.g., tryptamine). The CYP2D family has been identified in rodent, canine, and primate brain. Conversion of dextromethorphan to dextrorphan by rat brain membranes was assayed by HPLC and was dependent on NADPH, protein concentration, and incubation time. Significant loss of activity was observed in some homogenizing buffers and after freezing of whole tissues or membrane preparations. Dextromethorphan (0.5-640 microM) metabolism was mediated by high- and low-affinity enzyme systems; K(m1) was 2.7 +/- 2.6 and K(m2) was 757 +/- 156 microM (n = 3 rats, mean +/- S.E.). The enzyme activity was significantly (p <.01) and stereoselectively inhibited by CYP2D1 inhibitors quinine and quinidine (not by CYP2C or CYP3A inhibitors), and by anti-CYP2D6 peptide antiserum (not by anti-CYP2C, -CYP2B, or -CYP3A antibodies). The enzymatic activity demonstrated significant brain regional variation (n = 10 regions, p <.001). These data characterize CYP2D1-mediated dextromethorphan metabolism in rat brain and suggest that localized metabolism of other CYP2D1 substrates (drugs, neurotoxins, and possibly endogenous compounds) within the brain will occur. In humans, CYP2D6 is genetically polymorphic; the variable expression of brain CYP2D6 may result in interindividual differences in central drug and neurotoxin metabolism, possibly contributing to interindividual differences in drug effects and neurotoxicity.

  11. Prediction of Relative In Vivo Metabolite Exposure from In Vitro Data Using Two Model Drugs: Dextromethorphan and Omeprazole

    PubMed Central

    Lutz, Justin D.

    2012-01-01

    Metabolites can have pharmacological or toxicological effects, inhibit metabolic enzymes, and be used as probes of drug-drug interactions or specific cytochrome P450 (P450) phenotypes. Thus, better understanding and prediction methods are needed to characterize metabolite exposures in vivo. This study aimed to test whether in vitro data could be used to predict and rationalize in vivo metabolite exposures using two model drugs and P450 probes: dextromethorphan and omeprazole with their primary metabolites dextrorphan, 5-hydroxyomeprazole (5OH-omeprazole), and omeprazole sulfone. Relative metabolite exposures were predicted using metabolite formation and elimination clearances. For dextrorphan, the formation clearances of dextrorphan glucuronide and 3-hydroxymorphinan from dextrorphan in human liver microsomes were used to predict metabolite (dextrorphan) clearance. For 5OH-omeprazole and omeprazole sulfone, the depletion rates of the metabolites in human hepatocytes were used to predict metabolite clearance. Dextrorphan/dextromethorphan in vivo metabolite/parent area under the plasma concentration versus time curve ratio (AUCm/AUCp) was overpredicted by 2.1-fold, whereas 5OH-omeprazole/omeprazole and omeprazole sulfone/omeprazole were predicted within 0.75- and 1.1-fold, respectively. The effect of inhibition or induction of the metabolite's formation and elimination on the AUCm/AUCp ratio was simulated. The simulations showed that unless metabolite clearance pathways are characterized, interpretation of the metabolic ratios is exceedingly difficult. This study shows that relative in vivo metabolite exposure can be predicted from in vitro data and characterization of secondary metabolism of probe metabolites is critical for interpretation of phenotypic data. PMID:22010218

  12. The utility of the combination of dextromethorphan and quinidine in the treatment of bipolar II and bipolar NOS.

    PubMed

    Kelly, Tammas Frederick; Lieberman, Daniel Z

    2014-01-01

    Dextromethorphan is an over-the-counter antitussive agent that may be a rapidly acting treatment for bipolar depression. Like ketamine, it is an NMDA receptor antagonist. We conducted a retrospective chart review of depressed patients with treatment resistant bipolar II or bipolar NOS disorder who were treated with the combination of dextromethorphan 20 mg and quinidine 10 mg (DMQ). One pill of DMQ taken once or twice a day was added to participants׳ drug regimen. No changes were made to the pre-existing drug regimen during the course of treatment with DMQ. The primary outcome measure was the Clinical Global Impression-Improvement (CGI-I) score after 90 days of treatment. Seventy-seven participants met the inclusion criteria. All had been experiencing depressive symptoms for at least two years, and the mean number of failed medication trials was 21.2. The average CGI-I score at day 90 was 1.66 (1=slightly improved, 2=much improved). Some patients reported improvement within 1-2 days of starting DMQ. Nineteen patients discontinued treatment due to adverse effects, chiefly nausea. Because this was a retrospective chart review with no control group, conclusions about causation cannot be made. Nevertheless, the duration of depressive symptoms prior to starting DMQ makes spontaneous recovery less likely. DMQ, an NMDA antagonist, may be effective in the treatment of bipolar depression. Because its putative mechanism does not depend on the monoaminergic system, it may be appropriate for patients who have not responded to other medications. Unlike ketamine, DMQ does not require i.v. administration. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Mecamylamine, dihydro-β-erythroidine, and dextromethorphan block conditioned responding evoked by the conditional stimulus effects of nicotine

    PubMed Central

    Struthers, Amanda M.; Wilkinson, Jamie L.; Dwoskin, Linda P.; Crooks, Peter A.; Bevins, Rick A.

    2009-01-01

    Current smokers express the desire to quit. However, the majority find it difficult to remain abstinent. As such, research efforts continually seek to develop more effective treatment. One such area of research involves the interoceptive stimulus effects of nicotine as either a discriminative stimulus in an operant drug discrimination task, or more recently as a conditional stimulus (CS) in a discriminated goal-tracking task. The present work investigated the potential role nicotinic acetylcholine receptors in the CS effects of nicotine (0.4 mg/kg) using antagonists with differential selectivity for β2*, α7*, α6β2*, and α3β4* receptors. Methyllycaconitine (MLA) had no effect on nicotine-evoked conditioned responding. Mecamylamine and dihydro-β-erythroidine (DHβE) dose dependently blocked responding evoked by the nicotine CS. In a time-course assessment of mecamylamine and DHβE, each blocked conditioned responding when given 5 min before testing and still blocked conditioned responding when administered 200 min before testing. Two novel bis-picolinium analogs (N, N’-(3, 3′-(dodecan-1,12-diyl)-bis-picolinium dibromide [bPiDDB], and N, N’-(decan-1,10-diyl)-bis-picolinium diiodide [bPiDI]) did not block nicotine-evoked conditioned responding. Finally, pretreatment with low dose combinations of mecamylamine, dextromethorphan, and/or bupropion were used to target α3β4* receptors. No combination blocked conditioned responding evoked by the training dose of nicotine. However, a combination of mecamylamine and dextromethorphan partially blocked nicotine-evoked conditioned responding to a lower dose of nicotine (0.1 mg/kg). These results indicate that β2* and potentially α3β4* nicotinic acetylcholine receptors play a role in the CS effects of nicotine and are potential targets for the development of nicotine cessation aids. PMID:19778551

  14. Simultaneous determination of dextromethorphan, dextrorphan and doxylamine in human plasma by HPLC coupled to electrospray ionization tandem mass spectrometry: application to a pharmacokinetic study.

    PubMed

    Donato, J L; Koizumi, F; Pereira, A S; Mendes, G D; De Nucci, G

    2012-06-15

    In the present study, a fast, sensitive and robust method to quantify dextromethorphan, dextrorphan and doxylamine in human plasma using deuterated internal standards (IS) is described. The analytes and the IS were extracted from plasma by a liquid-liquid extraction (LLE) using diethyl-ether/hexane (80/20, v/v). Extracted samples were analyzed by high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Chromatographic separation was performed by pumping the mobile phase (acetonitrile/water/formic acid (90/9/1, v/v/v) during 4.0min at a flow-rate of 1.5 mL min⁻¹ into a Phenomenex Gemini® C18, 5 μm analytical column (150 × 4.6 mm i.d.). The calibration curve was linear over the range from 0.2 to 200 ng mL⁻¹ for dextromethorphan and doxylamine and 0.05 to 10 ng mL⁻¹ for dextrorphan. The intra-batch precision and accuracy (%CV) of the method ranged from 2.5 to 9.5%, and 88.9 to 105.1%, respectively. Method inter-batch precision (%CV) and accuracy ranged from 6.7 to 10.3%, and 92.2 to 107.1%, respectively. The run-time was for 4 min. The analytical procedure herein described was used to assess the pharmacokinetics of dextromethorphan, dextrorphan and doxylamine in healthy volunteers after a single oral dose of a formulation containing 30 mg of dextromethorphan hydrobromide and 12.5mg of doxylamine succinate. The method has high sensitivity, specificity and allows high throughput analysis required for a pharmacokinetic study.

  15. Liquid chromatography/quadrupole-time-of-flight mass spectrometry with metabolic profiling of human urine as a tool for environmental analysis of dextromethorphan.

    PubMed

    Thurman, E Michael; Ferrer, Imma

    2012-10-12

    We use the combination of liquid chromatography/quadrupole-time-of-flight mass spectrometry (LC/Q-TOF-MS) and urine metabolic profiling to find and identify the metabolites of dextromethorphan, a common over-the-counter (OTC) cough suppressant. Next, we use the combination of ion masses, their MS/MS fragmentation, and retention times to determine dextromethorphan and its metabolites in surface water impacted by wastewater. Prior to this study, neither dextromethorphan nor its metabolites have been reported in surface water; in spite of its common use in over 100 various OTC medications. We found that the concentration of the dextrorphan metabolite in surface water greatly exceeded the parent compound by factors of 5-10 times, which reflects the urine profile, where parent compound is approximately <2% of the total excreted drug based on ion intensities. Urine profiling also indicated that glucuronide metabolites are major phase 2 products (92% of the total) in urine and then are completely hydrolyzed in wastewater to dextrorphan and N-demethyldextrorphan, which are phase 1 metabolites-a "kind of reversal" of human metabolism. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Combination With Low-dose Dextromethorphan Improves the Effect of Amlodipine Monotherapy in Clinical Hypertension

    PubMed Central

    Yin, Wei-Hsian; Chen, Pei; Yeh, Hung-I; Wang, Kuo-Yang; Hung, Yi-Jen; Tseng, Wei-Kung; Wen, Ming-Shien; Wu, Tao-Cheng; Wu, Chau-Chung; Cheng, Shu-Meng; Chen, Jaw-Wen

    2016-01-01

    Abstract The combination of low rather than high dose of dextromethorphan (DXM) with amlodipine (AM) could improve blood pressure (BP) reduction in hypertensive animals. The study aimed to evaluate the feasibility of different doses of DXM combined with standard AM treatment in clinical hypertension. This was a prospective, 14-week, dose-escalation, multicenter study. After 2-week run-in period with AM 5 mg/day, hypertensive patients who got the BP goal of 140/90 mmHg kept receiving AM monotherapy for another 12 weeks. The nonresponders, while kept on AM 5 mg/day, received additional DXM treatment for 3 sequential dose-titrated periods with initially 2.5 mg/day, followed by 7.5 mg/day, and finally 30 mg/day. Each period was for 4 weeks. The patients at BP goal after each treatment period were defined as the responders and kept on the same combination till the end of the study. The responder rate of each treatment period was recorded. The changes of BP and serum antioxidant/endothelial markers between week 14 and week 2 were evaluated. Of the 103 patients initially enrolled, 89 entered the treatment period. In the 78 patients completing the study, 31 (40%) at BP goal after 2-week AM run-in kept on AM monotherapy (DXM0). The addition of 2.5 (DXM2.5) and 7.5 mg/day (DXM7.5) of DXM enabled BP goal achievement in 22 (47%) nonresponders to AM monotherapy including 16 (29%) with DXM2.5 and 6 (18%) with DXM7.5. Only 4 patients (16%) reached BP goal with the combination of DXM 30 mg/day (DXM30). Overall, 73% of the 78 patients reached BP goal at the end of the 14-week study. Mean systolic BP was reduced by 7.9% ± 7.0% with DXM2.5 (P < 0.001) and by 5.4% ± 2.4% with DXM7.5 (P = 0.003) respectively at week 14 from that at week 2, which was unchanged in either DXM0 or DXM30 group. Besides, the effects of combination treatment were particularly significant in the patients with impaired endothelial function suggested by reduced serum NOx level

  17. Synthesis, in vitro and in vivo studies, and molecular modeling of N-alkylated dextromethorphan derivatives as non-competitive inhibitors of α3β4 nicotinic acetylcholine receptor.

    PubMed

    Jozwiak, Krzysztof; Targowska-Duda, Katarzyna M; Kaczor, Agnieszka A; Kozak, Joanna; Ligeza, Agnieszka; Szacon, Elzbieta; Wrobel, Tomasz M; Budzynska, Barbara; Biala, Grazyna; Fornal, Emilia; Poso, Antti; Wainer, Irving W; Matosiuk, Dariusz

    2014-12-15

    9 N-alkylated derivatives of dextromethorphan are synthesized and studied as non-competitive inhibitors of α3β4 nicotinic acetylcholine receptors (nAChRs). In vitro activity towards α3β4 nicotinic acetylcholine receptor is determined using a patch-clamp technique and is in the micromolar range. Homology modeling, molecular docking and molecular dynamics of ligand-receptor complexes in POPC membrane are used to find the mode of interactions of N-alkylated dextromethorphan derivatives with α3β4 nAChR. The compounds, similarly as dextromethorphan, interact with the middle portion of α3β4 nAChR ion channel. Finally, behavioral tests confirmed potential application of the studied compounds for the treatment of addiction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. ALDH2 polymorphism, associated with attenuating negative symptoms in patients with schizophrenia treated with add-on dextromethorphan.

    PubMed

    Lee, Sheng-Yu; Chen, Shiou-Lan; Chang, Yun-Hsuan; Chen, Po-See; Huang, San-Yuan; Tzeng, Nian-Sheng; Wang, Liang-Jen; Lee, I-Hui; Wang, Tzu-Yun; Chen, Kao-Chin; Yang, Yen-Kuang; Hong, Jau-Shyong; Lu, Ru-Band

    2015-10-01

    Increasing the evidence of inflammation's contribution to schizophrenia; using anti-inflammatory or neurotrophic therapeutic agents to see whether they improve schizophrenia treatment. Dextromethorphan (DM), a non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist, might protect monoamine neurons. Whether treating schizophrenia with risperidone plus add-on DM is more effective than risperidone (RISP) alone, and the association between the ALDH2 polymorphism and treatment response were investigated. A double-blind study in which patients with schizophrenia were randomly assigned to the RISP + DM (60 mg/day; n = 74) or the RISP + Placebo (n = 75) group. The Positive and Negative Syndrome Scale (PANSS) and the Scale for the Assessment of Negative Symptoms (SANS) scores were used to evaluate clinical response during weeks 0, 1, 2, 4, 6, 8, and 11. The genotypes of the ALDH2 polymorphism were determined using polymerase chain reactions plus restriction fragment length polymorphism analysis. A generalized estimating equation was used to analyze the effects of ALDH2 polymorphism on the clinical performance of DM. PANSS and SANS scores were significantly lower in both groups after 11 weeks of treatment. SANS total scores were significantly lower in the RISP + DM group in patients with the ALDH2*2*2 genotype. RISP plus add-on DM treatment reduced negative schizophrenia symptoms in patients with the ALDH2 polymorphism. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Potential transducers based man-tailored biomimetic sensors for selective recognition of dextromethorphan as an antitussive drug.

    PubMed

    El-Naby, Eman H; Kamel, Ayman H

    2015-09-01

    A biomimetic potentiometric sensor for specific recognition of dextromethorphan (DXM), a drug classified according to the Drug Enforcement Administration (DEA) as a "drug of concern", is designed and characterized. A molecularly imprinted polymer (MIP), with special molecular recognition properties of DXM, was prepared by thermal polymerization in which DXM acted as template molecule, methacrylic acid (MAA) and acrylonitrile (AN) acted as functional monomers in the presence of ethylene glycol dimethacrylate (EGDMA) as crosslinker. The sensors showed a high selectivity and a sensitive response to the template in aqueous system. Electrochemical evaluation of these sensors revealed near-Nernstian response with slopes of 49.6±0.5 and 53.4±0.5 mV decade(-1) with a detection limit of 1.9×10(-6), and 1.0×10(-6) mol L(-1) DXM with MIP/MAA and MIP/AN membrane based sensors, respectively. Significantly improved accuracy, precision, response time, stability, selectivity and sensitivity were offered by these simple and cost-effective potentiometric sensors compared with other standard techniques. The method has the requisite accuracy, sensitivity and precision to assay DXM in pharmaceutical products. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Pharmacokinetic Effects of Isavuconazole Coadministration With the Cytochrome P450 Enzyme Substrates Bupropion, Repaglinide, Caffeine, Dextromethorphan, and Methadone in Healthy Subjects

    PubMed Central

    Yamazaki, Takao; Desai, Amit; Goldwater, Ronald; Han, David; Howieson, Corrie; Akhtar, Shahzad; Kowalski, Donna; Lademacher, Christopher; Pearlman, Helene; Rammelsberg, Diane

    2016-01-01

    Abstract This report describes phase 1 clinical trials performed to assess interactions of oral isavuconazole at the clinically targeted dose (200 mg, administered as isavuconazonium sulfate 372 mg, 3 times a day for 2 days; 200 mg once daily [QD] thereafter) with single oral doses of the cytochrome P450 (CYP) substrates: bupropion hydrochloride (CYP2B6; 100 mg; n = 24), repaglinide (CYP2C8/CYP3A4; 0.5 mg; n = 24), caffeine (CYP1A2; 200 mg; n = 24), dextromethorphan hydrobromide (CYP2D6/CYP3A4; 30 mg; n = 24), and methadone (CYP2B6/CYP2C19/CYP3A4; 10 mg; n = 23). Compared with each drug alone, coadministration with isavuconazole changed the area under the concentration‐time curves (AUC∞) and maximum concentrations (Cmax) as follows: bupropion, AUC∞ reduced 42%, Cmax reduced 31%; repaglinide, AUC∞ reduced 8%, Cmax reduced 14%; caffeine, AUC∞ increased 4%, Cmax reduced 1%; dextromethorphan, AUC∞ increased 18%, Cmax increased 17%; R‐methadone, AUC∞ reduced 10%, Cmax increased 3%; S‐methadone, AUC∞ reduced 35%, Cmax increased 1%. In all studies, there were no deaths, 1 serious adverse event (dextromethorphan study; perioral numbness, numbness of right arm and leg), and adverse events leading to study discontinuation were rare. Thus, isavuconazole is a mild inducer of CYP2B6 but does not appear to affect CYP1A2‐, CYP2C8‐, or CYP2D6‐mediated metabolism. PMID:27273149

  1. Further characterization of a ¹³C-dextromethorphan breath test for CYP2D6 phenotyping in breast cancer patients on tamoxifen therapy.

    PubMed

    Opdam, F L; Modak, A S; Gelderblom, H; Guchelaar, H J

    2015-04-20

    In a previous study, we found that the CYP2D6 phenotype determined by (13)C-dextromethorphan breath test (DM-BT) might be used to predict tamoxifen treatment outcome in breast cancer patients in the adjuvant setting. However, large variation in the delta-over-baseline (DOB) values was observed in the extensive metabolizer predicted phenotype group based on single point measures. In the present work we aimed to analyze the variability of phenotype results and determine reproducibility to further characterize the clinical utility of DM-BT by introducing multiple breath sampling instead of single breath sampling and by administration of a fixed dose of (13)C-DM.

  2. Binding of bufuralol, dextromethorphan, and 3,4-methylenedioxymethylamphetamine to wild-type and F120A mutant cytochrome P450 2D6 studied by resonance Raman spectroscopy

    SciTech Connect

    Bonifacio, Alois . E-mail: zwan@few.vu.nl

    2006-05-12

    Cytochrome P450 2D6 (CYP2D6) is one of the most important drug-metabolizing enzymes in humans. Resonance Raman data, reported for First time for CYP2D6, show that the CYP2D6 heme is found to be in a six-coordinated low-spin state in the absence of substrates, and it is perturbed to different extents by bufuralol, dextromethorphan, and 3,4-methylenedioxymethylamphetamine (MDMA). Dextromethorphan and MDMA induce in CYP2D6 a significant amount of five-coordinated high-spin heme species and reduce the polarity of its heme-pocket, whereas bufuralol does not. Spectra of the F120A mutant CYP2D6 suggest that Phe{sup 12} is involved in substrate-binding of dextromethorphan and MDMA, being responsible for the spectral differences observed between these two compounds and bufuralol. These differences could be explained postulating a different substrate mobility for each compound in the CYP2D6 active site, consistently with the role previously suggested for Phe{sup 12} in binding dextromethorphan and MDMA.

  3. Influence of Carbopol 71G-NF on the release of dextromethorphan hydrobromide from extended-release matrix tablets.

    PubMed

    Fayed, Mohamed H; Mahrous, Gamal M; Ibrahim, Mohamed A; Sakr, Adel

    2013-01-01

    The objective of this study was to evaluate the potential of Carbopol(®) 71G-NF on the release of dextromethorphan hydrobromide (DM) from matrix tablets in comparison with hydroxypropyl methylcellulose (HPMC(®) K15M) and Eudragit(®) L100-55 polymers. Controlled release DM matrix tablets were prepared using Carbopol 71G-NF, HPMC K15M, and Eudragit L100-55 at different drug to polymer ratios by direct compression technique. The mechanical properties of the tablets as tested by crushing strength and friability tests were improved as the concentration of Carbopol, HPMC, and Eudragit increased. However, Carbopol-based tablets showed a significantly (P<0.05) higher crushing strength and a lower friability than HPMC and Eudragit tablets. No significant differences in weight uniformity and thickness values were observed between the different formulations. It was also found that Carbopol significantly (P<0.05) delayed the release of DM in comparison with HPMC K15M and Eudragit L100-55. A combination of HPMC K15M and Eudragit L100-55 in a 1:1 ratio at 20 and 30% significantly (P<0.05) delayed the release of DM than Eudragit L100-55 alone. Moreover, blends of Carbopol and HPMC at a 1:1 ratio at the 10, 20, and 30% total polymer concentration were investigated. The blend of Carbopol and HPMC at 10% level significantly (P<0.05) slowed the release of DM than Carbopol or HPMC alone, whereas blends at 20 and 30% level significantly (P<0.05) delayed the release of DM compared with HPMC or Carbopol alone. The results with these polymer blends showed that it was possible to reduce the total amount of polymers when used as a combination in formulation.

  4. Role of hippocampal and prefrontal cortical signaling pathways in dextromethorphan effect on morphine-induced memory impairment in rats.

    PubMed

    Ghasemzadeh, Zahra; Rezayof, Ameneh

    2016-02-01

    Evidence suggests that dextromethorphan (DM), an NMDA receptor antagonist, induces memory impairment. Considering that DM is widely used in cough-treating medications, and the co-abuse of DM with morphine has recently been reported, the aims of the present study was (1) to investigate whether there is a functional interaction between morphine and DM in passive avoidance learning and (2) to assess the possible role of the hippocampal and prefrontal cortical (PFC) signaling pathways in the effects of the drugs on memory formation. Our findings indicated that post-training or pre-test administration of morphine (2 and 6 mg/kg) or DM (10-30 mg/kg) impaired memory consolidation and retrieval which was associated with the attenuation of the levels of phosphorylated Ca(2+)/calmodulin-dependent protein kinase II (p-CAMKII) and cAMP responsive element-binding protein (p-CREB) in the targeted sites. Moreover, the memory impairment induced by post-training administration of morphine was reversed by pre-test administration of the same dose of morphine or DM (30 mg/kg), indicating state-dependent learning (SDL) and a cross-SDL between the drugs. It is important to note that the levels of p-CAMKII/CAMKII and p-CREB/CREB in the hippocampus and the PFC increased in drugs-induced SDL. In addition, DM administration potentiated morphine-induced SDL which was related to the enhanced levels of hippocampal and PFC CAMKII-CREB signaling pathways. It can be concluded that there is a relationship between the hippocampus and the PFC in the effect of DM and/or morphine on memory retrieval. Moreover, a cross SDL can be induced between the co-administration of DM and morphine. Interestingly, CAMKII-CREB signaling pathways also mediate the drugs-induced SDL.

  5. Treatment Resistant Depression with Loss of Antidepressant Response: Rapid—Acting Antidepressant Action of Dextromethorphan, A Possible Treatment Bridging Molecule

    PubMed Central

    Lauterbach, Edward C.

    2016-01-01

    Dextromethorphan (DM) may have ketamine—like rapid—acting, treatment—resistant, and conventional antidepressant effects.1,2 This reports our initial experience with DM in unipolar Major Depressive Disorder (MDD). A patient with treatment—resistant MDD (failing adequate trials of citalopram and vortioxetine) with loss of antidepressant response (to fluoxetine and bupropion) twice experienced a rapid—acting antidepressant effect within 48 hours of DM administration and lasting 7 days, sustained up to 20 days with daily administration, then gradually developing labile loss of antidepressant response over the ensuing 7 days. Upon full relapse in DSM-5 MDD while taking 600 mg/day of the strong CYP2D6 inhibitor bupropion XL, a 300 mg oral loading dose of DM was given, followed by 60 mg po bid after an additional dose—finding period, without side effects. DM exhibited a ketamine—like rapid—acting antidepressant effect, thought to be mediated by mTOR activation (related to NMDA PCP site antagonism, sigma-1 and beta adrenergic receptor stimulation) and 5HTT inhibition, resulting in AMPA receptor trafficking, and dendritogenesis, spinogenesis, synaptogenesis, and increased neuronal survival (related to NMDA antagonism and sigma-1 and mTOR signaling). This report appears to be the first report of a rapid—acting effect in unipolar MDD and adds to antidepressant effects observed in the retrospective chart review of 77 patients with Bipolar II Disorder (Kelly and Lieberman 2014). If replicated, there is some reason to think that the administration of other agents with DM, such as lithium or D-cycloserine, might prolong the duration of the rapid-antidepressant effect. PMID:27738380

  6. Dextromethorphan provides neuroprotection via anti-inflammatory and anti-excitotoxicity effects in the cortex following traumatic brain injury.

    PubMed

    Pu, Benfang; Xue, Yonghua; Wang, Qingming; Hua, Chunhui; Li, Xinyuan

    2015-09-01

    Traumatic brain injury (TBI) is caused by primary and secondary injury mechanisms. TBI induces a certain amount of inflammatory responses and glutamate excitotoxicity that are believed to participate in the pathogenesis of secondary injury. The non‑narcotic anti‑tussive drug dextromethorphan (DM) has been reported to have a high safety profile in humans and its neuroprotective against a variety of disorders, including cerebral ischemia, epilepsy and acute brain injury. However, few studies have explored the underlying mechanisms of the neuroprotective effects of DM in animals in the setting of TBI. The aim of the present study was to investigate the neuroprotective effects of DM on TBI and to determine the underlying mechanisms. Rats were subjected to a controlled cortical impact (CCI) injury and randomly divided into three groups: Sham‑operated, TBI and DM treatment groups. The DM treatment group was administered DM (30 mg/kg of body weight, intraperitoneally) immediately after injury. It was identified that DM treatment following TBI significantly reduced brain edema and neurological deficits, as well as increased neuronal survival. These effects correlated with a decrease of tumor necrosis factor α, interleukin‑1β (IL‑1β) and IL‑6 protein expression and an increase of glutamate/aspartate transporter and glutamate transporter‑1 in the cortex of the brain. These results provided in vivo evidence that DM exerts neuroprotective effects via reducing inflammation and excitotoxicity induced following TBI. The present study has shed light on the potential use of DM as a neuroprotective agent in the treatment of cerebral injuries.

  7. Low-Dose Dextromethorphan, a NADPH Oxidase Inhibitor, Reduces Blood Pressure and Enhances Vascular Protection in Experimental Hypertension

    PubMed Central

    Wu, Tao-Cheng; Chao, Chih-Yu; Lin, Shing-Jong; Chen, Jaw-Wen

    2012-01-01

    Background Vascular oxidative stress may be increased with age and aggravate endothelial dysfunction and vascular injury in hypertension. This study aimed to investigate the effects of dextromethorphan (DM), a NADPH oxidase inhibitor, either alone or in combination treatment, on blood pressure (BP) and vascular protection in aged spontaneous hypertensive rats (SHRs). Methodology/Principal Findings Eighteen-week-old WKY rats and SHRs were housed for 2 weeks. SHRs were randomly assigned to one of the 12 groups: untreated; DM monotherapy with 1, 5 or 25 mg/kg/day; amlodipine (AM, a calcium channel blocker) monotherapy with 1 or 5 mg/kg/day; and combination therapy of DM 1, 5 or 25 mg/kg/day with AM 1 or 5 mg/kg/day individually for 4 weeks. The in vitro effects of DM were also examined. In SHRs, AM monotherapy dose-dependently reduced arterial systolic BP. DM in various doses significantly and similarly reduced arterial systolic BP. Combination of DM with AM gave additive effects on BP reduction. DM, either alone or in combination with AM, improved aortic endothelial function indicated by ex vivo acetylcholine-induced relaxation. The combination of low-dose DM with AM gave most significant inhibition on aortic wall thickness in SHRs. Plasma total antioxidant status was significantly increased by all the therapies except for the combination of high-dose DM with high-dose AM. Serum nitrite and nitrate level was significantly reduced by AM but not by DM or the combination of DM with AM. Furthermore, in vitro treatment with DM reduced angiotensin II-induced reactive oxygen species and NADPH oxidase activation in human aortic endothelial cells. Conclusions/Significance Treatment of DM reduced BP and enhanced vascular protection probably by inhibiting vascular NADPH oxidase in aged hypertensive animals with or without AM treatment. It provides the potential rationale to a novel combination treatment with low-dose DM and AM in clinical hypertension. PMID:23049937

  8. The COMT Val158Met Polymorphism Is Associated With Response to Add-on Dextromethorphan Treatment in Bipolar Disorder.

    PubMed

    Lee, Sheng-Yu; Chen, Shiou-Lan; Wang, Tzu-Yun; Chang, Yun-Hsuan; Chen, Po See; Huang, San-Yuan; Tzeng, Nian-Sheng; Wang, Liang-Jen; Lee, I Hui; Chen, Kao Ching; Yang, Yen Kuang; Lu, Ru-Band

    2017-02-01

    We previously conducted a randomized, double-blind, controlled, 12-week study evaluating the effect of add-on dextromethorphan (DM), a noncompetitive N-methyl-D-aspartate receptor antagonist, on patients with bipolar disorder (BD) treated using valproate (VPA), which showed negative clinical differences. The genetic variation between each individual may be responsible for interindividual differences. The catechol-O-methyltransferase (COMT) gene has been a candidate gene for BD. In the current study, we investigated whether the COMT Val158Met polymorphism predicts treatment response to VPA + add-on DM and to VPA + placebo. Patients with BD (n = 309) undergoing regular VPA treatments were randomly assigned to groups given either add-on DM (30 mg/d) (n = 102), DM (60 mg/d) (n = 101), or placebo (n = 106) for 12 weeks. The Hamilton Depression Rating Scale and Young Mania Rating Scale were used to evaluate clinical response during weeks 0, 1, 2, 4, 8, and 12. The genotypes of the COMT Val158Met polymorphism were determined using polymerase chain reaction plus restriction fragment length polymorphism analysis. To adjust for within-subject dependence over repeated assessments, multiple linear regression with generalized estimating equation methods was used. When stratified by the COMT Val158Met genotypes, significantly greater decreases in Hamilton Depression Rating Scale scores were found in the VPA + DM (30 mg/d) group in patients with the Val/Met genotype (P = 0.008). We conclude that the COMT Val158Met polymorphism may influence responses to DM (30 mg/d) by decreasing depressive symptoms in BD patients.

  9. Dextromethorphan attenuated the higher vulnerability to inflammatory thermal hyperalgesia caused by prenatal morphine exposure in rat offspring

    PubMed Central

    2011-01-01

    Background Co-administration of dextromethorphan (DM) with morphine during pregnancy and throughout lactation has been found to reduce morphine physical dependence and tolerance in rat offspring. No evidence was presented, however, for the effect of DM co-administered with morphine during pregnancy on inflammatory hyperalgesia in morphine-exposed offspring. Therefore, we attempt to investigate the possible effect of prenatal morphine exposure on the vulnerability to hyperalgesia and the possible therapeutic effect of DM in the present study. Methods Fifty μl of carrageenan (20 mg/ml) was injected subcutaneously into the plantar surface of the right hind paw in p18 rats to induce hyperalgesia. Mean paw withdrawal latency was measured in the plantar test to index the severity of hyperalgesia. Using Western blotting and RT-PCR, the quantitative analyses of NMDA receptor NR1 and NR2B subunits were performed in spinal cords from different groups of animals. Results In the carrageenan-induced hyperalgesia model, rat offspring passively exposed to morphine developed a severe hyperalgesia on postnatal day 18 (p18), which also had a more rapid time course than those in the controls. Co-administration of DM with morphine in the dams prevented this adverse effect of morphine in the offspring rats. Western blot and RT-PCR analysis showed that the levels of protein and mRNA of NMDA receptor NR1 and NR2B subunits were significantly higher in the lumbar spinal cords of rats (p14) exposed to prenatal morphine; the co-administration of DM could reverse the effect of morphine on NR1 and attenuate the effect on NR2B. Conclusions Thus, DM may have a great potential in the prevention of higher vulnerability to inflammatory thermal hyperalgesia in the offspring of morphine-addicted mothers. PMID:21861871

  10. SKF 525-A and cytochrome P-450 ligands inhibit with high affinity the binding of ( sup 3 H)dextromethorphan and. sigma. ligands to guinea pig brain

    SciTech Connect

    Klein, M.; Canoll, P.D.; Musacchio, J.M. )

    1991-01-01

    The DM{sub 1}/{sigma}{sub 1} site binds dextromethorphan (DM) and {sigma} receptor ligands. The broad binding specificity of this site and its peculiar subcellular distribution prompted us to explore the possibility that this site is a member of the cytochrome P-450 superfamily of enzymes. We tested the effects of the liver microsomal monooxygenase inhibitor SKF 525-A (Proadifen), and other P-450 substrates on the binding of ({sup 3}H)dextromethorphan, ({sup 3}H)3- (3-Hydroxyphenyl) -N- (1-propyl) piperidine and (+)-({sup 3}H)1,3-Di-o-tolyl-guanidine (({sup 3}H)DTG) to the guinea pig brain. SKF 525-A, l-lobeline and GBR-12909 inhibited the binding of the three labeled ligands with nM affinity. Each drug has identical nM K{sub i} values for the high-affinity site labeled by the three ligands. This indicated that they displaced the labeled ligands from the common DM{sub 1}{sigma}{sub 1} site. Debrisoquine and sparteine, prototypical substrates for liver debrisoquine 4-hydroxylase, displayed K{sub i} values of 9-13 and 3-4 {mu}M respectively against the three labeled ligands. These results, the broad specificity of the DM{sub 1}/{sigma}{sub 1} binding site, and its peculiar subcellular distribution, raises the possibility that this binding site is a member of the cytochrome P-450 superfamily of isozymes, rather than a neurotransmitter receptor.

  11. Effect of Curcuma longa on CYP2D6- and CYP3A4-mediated metabolism of dextromethorphan in human liver microsomes and healthy human subjects.

    PubMed

    Al-Jenoobi, Fahad Ibrahim; Al-Thukair, Areej A; Alam, Mohd Aftab; Abbas, Fawkeya A; Al-Mohizea, Abdullah M; Alkharfy, Khalid M; Al-Suwayeh, Saleh A

    2015-03-01

    Effect of Curcuma longa rhizome powder and its ethanolic extract on CYP2D6 and CYP3A4 metabolic activity was investigated in vitro using human liver microsomes and clinically in healthy human subjects. Dextromethorphan (DEX) was used as common probe for CYP2D6 and CYP3A4 enzymes. Metabolic activity of CYP2D6 and CYP3A4 was evaluated through in vitro study; where microsomes were incubated with NADPH in presence and absence of Curcuma extract. In clinical study phase-I, six healthy human subjects received a single dose (30 mg) of DEX syrup, and in phase-II DEX syrup was administered with Curcuma powder. The enzyme CYP2D6 and CYP3A4 mediated O- and N-demethylation of dextromethorphan into dextrorphan (DOR) and 3-methoxymorphinan (3-MM), respectively. Curcuma extract significantly inhibited the formation of DOR and 3-MM, in a dose-dependent and linear fashion. The 100 μg/ml dose of curcuma extract produced highest inhibition, which was about 70 % for DOR and 80 % for 3-MM. Curcuma significantly increases the urine metabolic ratio of DEX/DOR but the change in DEX/3-MM ratio was statistically insignificant. Present findings suggested that curcuma significantly inhibits the activity of CYP2D6 in in vitro as well as in vivo; which indicates that curcuma has potential to interact with CYP2D6 substrates.

  12. The role of NMDA receptor and nitric oxide/cyclic guanosine monophosphate pathway in the antidepressant-like effect of dextromethorphan in mice forced swimming test and tail suspension test.

    PubMed

    Sakhaee, Ehsan; Ostadhadi, Sattar; Khan, Muhammad Imran; Yousefi, Farbod; Norouzi-Javidan, Abbas; Akbarian, Reyhaneh; Chamanara, Mohsen; Zolfaghari, Samira; Dehpour, Ahmad-Reza

    2017-01-01

    Depression is a devastating disorder which has a high impact on the wellbeing of overall society. As such, need for innovative therapeutic agents are always there. Most of the researchers focused on N-methyl-d-aspartate receptor to explore the antidepressant like activity of new therapeutic agents. Dextromethorphan is a cough suppressant agent with potential antidepressant activity reported in mouse force swimming test. Considering N-methyl-d-aspartate as a forefront in exploring antidepressant agents, here we focused to unpin the antidepressant mechanism of dextromethorphan targeting N-methyl-d-aspartate receptor induced nitric oxide-cyclic guanosine monophosphate signaling. Dextromethorphan administered at a dose of 10 and 30mg/kg i.p significantly reduced the immobility time. Interestingly, this effect of drug (30mg/kg) was inhibited when the animals were pretreated either with N-methyl-d-aspartate (75mg/kg), or l-arginine (750mg/kg) as a nitric oxide precursor and/or sildenafil (5mg/kg) as a phosphodiesterase 5 inhibitor. However, the antidepressant effect of Dextromethorphan subeffective dose (3mg/kg) was augmented when the animals were administered with either L-NG-Nitroarginine methyl ester (10mg/kg) non-specific nitric oxide synthase inhibitor, 7-Nitroindazole (30mg/kg) specific neural nitric oxide synthase inhibitor, MK-801 (0.05mg/kg) an N-methyl-d-aspartate receptor antagonist but not aminoguanidine (50mg/kg) which is specific inducible nitric oxide synthase inhibitor as compared to the drugs when administered alone. No remarkable effect on locomotor activity was observed during open field test when the drugs were administered at the above mentioned doses. Therefore, it is evident that the antidepressant like effect of Dextromethorphan is owed due to its inhibitory effect on N-methyl-d-aspartate receptor and NO- Cyclic guanosine monophosphate pathway.

  13. Alternative methods for CYP2D6 phenotyping: comparison of dextromethorphan metabolic ratios from AUC, single point plasma, and urine.

    PubMed

    Chen, Rui; Wang, Haotian; Shi, Jun; Hu, Pei

    2016-05-01

    CYP2D6 is a high polymorphic enzyme. Determining its phenotype before CYP2D6 substrate treatment can avoid dose-dependent adverse events or therapeutic failures. Alternative phenotyping methods of CYP2D6 were compared to aluate the appropriate and precise time points for phenotyping after single-dose and ultiple-dose of 30-mg controlled-release (CR) dextromethorphan (DM) and to explore the antimodes for potential sampling methods. This was an open-label, single and multiple-dose study. 21 subjects were assigned to receive a single dose of CR DM 30 mg orally, followed by a 3-day washout period prior to oral administration of CR DM 30 mg every 12 hours for 6 days. Metabolic ratios (MRs) from AUC∞ after single dosing and from AUC0-12h at steady state were taken as the gold standard. The correlations of metabolic ratios of DM to dextrorphan (MRDM/DX) values based on different phenotyping methods were assessed. Linear regression formulas were derived to calculate the antimodes for potential sample methods. In the single-dose part of the study statistically significant correlations were found between MRDM/DX from AUC∞ and from serial plasma points from 1 to 30 hours or from urine (all p-values < 0.001). In the multiple-dose part, statistically significant correlations were found between MRDM/DX from AUC0-12h on day 6 and MRDM/DX from serial plasma points from 0 to 36 hours after the last dosing (all p-values < 0.001). Based on reported urinary antimode and linear regression analysis, the antimodes of AUC and plasma points were derived to profile the trend of antimodes as the drug concentrations changed. MRDM/DX from plasma points had good correlations with MRDM/DX from AUC. Plasma points from 1 to 30 hours after single dose of 30-mg CR DM and any plasma point at steady state after multiple doses of CR DM could potentially be used for phenotyping of CYP2D6.

  14. Therapeutic Approach of a High Functioning Individual With Traumatic Brain Injury and Subsequent Emotional Volatility With Features of Pathological Laughter and Crying With Dextromethorphan/Quinidine

    PubMed Central

    Garcia-Baran, Dynela; Johnson, Thomas M.; Wagner, Joyce; Shen, Joann; Geers, Michelle

    2016-01-01

    Abstract Pathological laughing and crying, or pseudobulbar affect (PBA), has been described in patients with neurological disorders such as multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, stroke, and traumatic brain injury (TBI) since the 19th century (Schiffer 2005). The syndrome is characterized by inappropriate episodes of laughing or crying after minor stimuli. It was first coined a disinhibition of cortical control by Kinnier Wilson in 1924. It was observed in brain disease and seen with mild TBI. It can impair social and occupational function and is largely underrecognized in clinical settings. PBA is usually treated with antidepressants and dopaminergic agents. In this case we treated a military recruit with TBI with Nuedexta—a dextromethorphan/Quinidine derivative with a subsequent decrease in his episodes. PMID:27015166

  15. Therapeutic Approach of a High Functioning Individual With Traumatic Brain Injury and Subsequent Emotional Volatility With Features of Pathological Laughter and Crying With Dextromethorphan/Quinidine.

    PubMed

    Garcia-Baran, Dynela; Johnson, Thomas M; Wagner, Joyce; Shen, Joann; Geers, Michelle

    2016-03-01

    Pathological laughing and crying, or pseudobulbar affect (PBA), has been described in patients with neurological disorders such as multiple sclerosis, amyotrophic lateral sclerosis, Alzheimer's disease, stroke, and traumatic brain injury (TBI) since the 19th century (Schiffer 2005). The syndrome is characterized by inappropriate episodes of laughing or crying after minor stimuli. It was first coined a disinhibition of cortical control by Kinnier Wilson in 1924. It was observed in brain disease and seen with mild TBI. It can impair social and occupational function and is largely underrecognized in clinical settings. PBA is usually treated with antidepressants and dopaminergic agents. In this case we treated a military recruit with TBI with Nuedexta-a dextromethorphan/Quinidine derivative with a subsequent decrease in his episodes.

  16. Alterations of postsynaptic density proteins in the hippocampus of rat offspring from the morphine-addicted mother: Beneficial effect of dextromethorphan.

    PubMed

    Yang, San Nan; Liu, Chieh-An; Chung, Mei-Yung; Huang, Hsin-Chun; Yeh, Geng-Chang; Wong, Chih-Shung; Lin, Wei-Wen; Yang, Chun-Hua; Tao, Pao-Luh

    2006-01-01

    Infants passively exposed to morphine or heroin through their addicted mothers usually develop characteristic withdrawal syndrome of morphine after birth. In such early life, the central nervous system exhibits significant plasticity and can be altered by various prenatal influences, including prenatal morphine exposure. Here we studied the effects of prenatal morphine exposure on postsynaptic density protein 95 (PSD-95), an important cytoskeletal specialization involved in the anchoring of the NMDAR and neuronal nitric oxide synthase (nNOS), of the hippocampal CA1 subregion from young offspring at postnatal day 14 (P14). We also evaluated the therapeutic efficacy of dextromethorphan, a widely used antitussive drug with noncompetitive antagonistic effects on NMDARs, for such offspring. The results revealed that prenatal morphine exposure caused a maximal decrease in PSD-95 expression at P14 followed by an age-dependent improvement. In addition, prenatal morphine exposure reduced not only the expression of nNOS and the phosphorylation of cAMP responsive element-binding protein at serine 133 (CREB(Serine-133)), but also the magnitude of long-term depression (LTD) at P14. Subsequently, the morphine-treated offspring exhibited impaired performance in long-term learning and memory at later ages (P28-29). Prenatal coadministration of dextromethorphan with morphine during pregnancy and throughout lactation could significantly attenuate the adverse effects as described above. Collectively, the study demonstrates that maternal exposure to morphine decreases the magnitude of PSD-95, nNOS, the phosphorylation of CREB(Serine-133), and LTD expression in hippocampal CA1 subregion of young offspring (e.g., P14). Such alterations within the developing brain may play a role for subsequent neurological impairments (e.g., impaired performance of long-term learning and memory). The results raise a possibility that postsynaptic density proteins could serve an important role, at least

  17. Efficacy and safety of dextromethorphan/quinidine at two dosage levels for diabetic neuropathic pain: a double-blind, placebo-controlled, multicenter study.

    PubMed

    Shaibani, Aziz I; Pope, Laura E; Thisted, Ronald; Hepner, Adrian

    2012-02-01

    To evaluate dextromethorphan coadministered with quinidine as treatment of diabetic peripheral neuropathic pain. In a 13-week, phase 3, randomized controlled trial, 379 adults with daily symmetric diabetic peripheral neuropathy (DPN) leg pain for ≥3 months received double-blind placebo, dextromethorphan/quinidine (DMQ) 45/30 mg, or DMQ 30/30 mg, administered once daily for 7 days and twice daily thereafter. Efficacy measures included four pain rating scales applied daily using patient diaries, and another two applied at five clinic visits. On all six scales, DMQ 45/30 mg was significantly superior to placebo, including the primary efficacy analysis, which utilized mixed-effects modeling to test all scores on an 11-point numerical Pain Rating Scale (P < 0.0001). Sensitivity analyses gave consistent results. Efficacy vs placebo was also seen for diary ratings of present pain intensity, and pain interference with sleep and with activities (all P < 0.0001). Among clinic visit assessments, DMQ 45/30 mg demonstrated greater leg pain relief (P = 0.0002) and greater reduction of leg pain intensity (P = 0.0286) vs placebo. The efficacy of DMQ 30/30 mg was numerically less than for 45/30 mg but for most outcomes remained significantly greater vs placebo. Adverse events were mostly mild or moderate and of expected types. Discontinuation for adverse events in the DMQ groups was at least twice as common as placebo. Throughout a 13-week trial, DMQ was effective, with an acceptable safety profile, for treatment of DPN pain. Other fixed-dose combinations of DMQ should be studied to improve overall tolerability while maintaining significant efficacy. Wiley Periodicals, Inc.

  18. Dextromethorphan and Quinidine

    MedlinePlus

    ... disease; condition in which the nerves that control muscle movement slowly die, causing the muscles to shrink and weaken) or multiple sclerosis (a ... and patients may experience weakness, numbness, loss of muscle coordination and problems with vision, speech, and bladder ...

  19. Efficacy of a single evening dose of syrup containing paracetamol, dextromethorphan hydrobromide, doxylamine succinate and ephedrine sulfate in subjects with multiple common cold symptoms.

    PubMed

    Mizoguchi, H; Wilson, A; Jerdack, G R; Hull, J D; Goodale, M; Grender, J M; Tyler, B A

    2007-04-01

    The aim of this study was to evaluate the efficacy of a single night-time dose of a syrup containing paracetamol, dextromethorphan hydrobromide, doxylamine succinate and ephedrine sulfate in subjects with multiple cold symptoms. A syrup containing 15 mg dextromethorphan hydrobromide, 7.5 mg doxylamine succinate, 600 mg paracetamol and 8 mg ephedrine sulfate (Wick MediNait produced by WICK Pharma, Germany, a subsidiary of Procter & Gamble GmbH; test syrup) or placebo (placebo syrup) for oral administration. This was a randomized, double-blind, placebo-controlled, multi-center, parallel design study. At enrollment, eligible subjects had to have at least moderate nasal congestion and a runny nose, at least mild cough and at least mild pain with one or more of the following: sore throat, sore chest, headache or body pain/aches. Subjects were randomized into either Group T (test syrup) or Group P (placebo syrup). On the evening of enrollment, subjects rated baseline symptoms, ingested the assigned study product and completed symptom-relief assessments at 3 hours post-dosing. Within one hour of awakening the following morning, subjects completed night-time symptom relief and sleep satisfaction assessments. All symptoms were recorded using an Interactive Voice Response system. Treatment comparisons were made after adjusting for the severity of baseline symptom using analysis of covariance. Of 485 subjects who took the study product, 432 (224 in Group T; 208 in Group P) were evaluable for analysis. For the primary endpoint (composite of nasal congestion/runny nose/cough/pain relief scores 3 hours post-dosing), subjects in Group T had clinically and statistically significantly greater relief than Group P (p = 0.0002). Each individual symptom score also showed statistically significant improvement at this time point (p < or = 0.017). The next morning, Group T continued to show clinically and statistically significant benefits over Group P on the composite score and each of

  20. Floating matrix dosage form for dextromethorphan hydrobromide based on gas forming technique: in vitro and in vivo evaluation in healthy volunteers.

    PubMed

    Hu, Liandong; Li, Li; Yang, Xun; Liu, Wei; Yang, Jianxue; Jia, Yanhong; Shang, Chuang; Xu, Hongxin

    2011-01-18

    The objective of this study was to develop the dextromethorphan hydrobromide sustained-release (DMB-SR) tablets using floating technique to prolong the gastric residence time and compared their pharmacokinetic behavior with conventional sustained release tablets. DMB-SR floating tablets were prepared employing hydroxypropyl methylcellulose (HPMC) as hydrophilic gel material, sodium bicarbonate as gas-generating agent and hexadecanol as floating assistant agent. An orthogonal experiment design method was used to select the optimized formulation. The floating tablets were evaluated for uniformity of weight, hardness, friability, drug content, floating characteristics, in vitro release and in vivo bioavailability. The optimized tablets were prepared with HPMC K4M 25 mg, sodium bicarbonate 20 mg and hexadecanol 18 mg. The prepared tablets could float within 3 min and maintain for more than 24 h. The data of physical parameters were all lie within the limits. Drug release at 12 h was more than 85%. The comparative pharmacokinetic study was performed by administration of the DMB-SR floating tablets and conventional DMB-SR tablets. The area under curve of plasma concentration-time (AUC) of floating tablets was slightly higher than that of reference tablets, T(max) was prolonged apparently. The results showed the floating tablets are a feasible approach for the sustained-release preparation of drugs, which have limited absorption sites in the stomach.

  1. An open-label study to assess safety, tolerability, and effectiveness of dextromethorphan/quinidine for pseudobulbar affect in dementia: PRISM II results.

    PubMed

    Doody, Rachelle S; D'Amico, Stephen; Cutler, Andrew J; Davis, Charles S; Shin, Paul; Ledon, Fred; Yonan, Charles; Siffert, João

    2016-12-01

    Dextromethorphan (DM)/quinidine (Q) is an approved treatment for pseudobulbar affect (PBA) based on trials in amyotrophic lateral sclerosis or multiple sclerosis. PRISM II evaluated DM/Q effectiveness and tolerability for PBA secondary to dementia, stroke, or traumatic brain injury; dementia cohort results are reported. This was an open-label, multicenter, 90 day trial; patients received DM/Q 20/10 mg twice daily. Primary outcome was change in Center for Neurologic Study-Lability Scale (CNS-LS) score. Secondary outcomes included PBA episode count and Clinical and Patient/Caregiver Global Impression of Change scores with respect to PBA (CGI-C/PGI-C). 134 patients were treated. CNS-LS improved by a mean (SD) of 7.2 (6.0) points at Day 90/Endpoint (P<.001) vs. baseline. PBA episodes were reduced 67.7% (P<.001) vs. baseline; global measures showed 77.5% CGI-C and 76.5% PGI-C "much"/"very much" improved. Adverse events included headache (7.5%), urinary tract infection (4.5%), and diarrhea (3.7%); few patients dropped out for adverse events (10.4%). DM/Q significantly reduced PBA symptoms in patients with dementia; reported adverse events were consistent with the known safety profile of DM/Q. Trial Registration clinicaltrials.gov identifier: NCT01799941.

  2. In vivo characterization of CYP2D6*12, *29 and *84 using dextromethorphan as a probe drug: a case report.

    PubMed

    Gaedigk, Andrea; Twist, Greyson P; Farrow, Emily G; Lowry, Jennifer A; Soden, Sarah E; Miller, Neil A

    2017-04-01

    CYP2D6*84 was first described in a Black South African subject, however, its function remains unknown. Astrolabe, a probabilistic scoring tool developed in our laboratory to call genotypes from whole genome sequence, identified CYP2D6*84 in a trio. The father presented with intermediate metabolism when challenged with the CYP2D6 probe drug dextromethorphan (DM/dextrorphan [DX] = 0.0839). Since his second allele, CYP2D6*12, is nonfunctional, the observed activity is derived by CYP2D6*84. This finding suggests that the allele's hallmark P267H causes decreased activity toward DM and that this allele should receive a value of 0.5 for Activity Score calculations. The mother's DM/DX of 0.0543 was consistent with the decreased activity classification of CYP2D6*29. The child, a critically ill neonate, was not phenotyped, but predicted to be a normal metabolizer.

  3. Simultaneous determination of dextromethorphan, dextrorphan, and guaifenesin in human plasma using semi-automated liquid/liquid extraction and gradient liquid chromatography tandem mass spectrometry.

    PubMed

    Eichhold, Thomas H; McCauley-Myers, David L; Khambe, Deepa A; Thompson, Gary A; Hoke, Steven H

    2007-01-17

    A method for the simultaneous determination of dextromethorphan (DEX), dextrorphan (DET), and guaifenesin (GG) in human plasma was developed, validated, and applied to determine plasma concentrations of these compounds in samples from six clinical pharmacokinetic (PK) studies. Semi-automated liquid handling systems were used to perform the majority of the sample manipulation including liquid/liquid extraction (LLE) of the analytes from human plasma. Stable-isotope-labeled analogues were utilized as internal standards (ISTDs) for each analyte to facilitate accurate and precise quantification. Extracts were analyzed using gradient liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Use of semi-automated LLE with LC-MS/MS proved to be a very rugged and reliable approach for analysis of more than 6200 clinical study samples. The lower limit of quantification was validated at 0.010, 0.010, and 1.0 ng/mL of plasma for DEX, DET, and GG, respectively. Accuracy and precision of quality control (QC) samples for all three analytes met FDA Guidance criteria of +/-15% for average QC accuracy with coefficients of variation less than 15%. Data from the thorough evaluation of the method during development, validation, and application are presented to characterize selectivity, linearity, over-range sample analysis, accuracy, precision, autosampler carry-over, ruggedness, extraction efficiency, ionization suppression, and stability. Pharmacokinetic data are also provided to illustrate improvements in systemic drug and metabolite concentration-time profiles that were achieved by formulation optimization.

  4. Attenuation by dextromethorphan on the higher liability to morphine-induced reward, caused by prenatal exposure of morphine in rat offspring.

    PubMed

    Wu, Ling-Yi; Chen, Jain-Fang; Tao, Pao-Luh; Huang, Eagle Yi-Kung

    2009-11-25

    Co-administration of dextromethorphan (DM) with morphine during pregnancy and throughout lactation has been found to reduce morphine physical dependence and tolerance in rat offspring. No evidence was presented, however, for the effect of DM co-administered with morphine during pregnancy on morphine-induced reward and behavioral sensitization (possibly related to the potential to induce morphine addiction) in morphine-exposed offspring. Conditioned place preference and locomotor activity tests revealed that the p60 male offspring of chronic morphine-treated female rats were more vulnerable to morphine-induced reward and behavioral sensitization. The administration of a low dose of morphine (1 mg/kg, i.p.) in these male offspring also increased the dopamine and serotonin turnover rates in the nucleus accumbens, which implied that they were more sensitive to morphine. Co-administration of DM with morphine in the dams prevented this adverse effect of morphine in the offspring rats. Thus, DM may possibly have a great potential in the prevention of higher vulnerability to psychological dependence of morphine in the offspring of morphine-addicted mothers.

  5. Effects of dextromethorphan on MDMA-induced serotonergic aberration in the brains of non-human primates using [123I]-ADAM/SPECT

    PubMed Central

    Ma, Kuo-Hsing; Liu, Tsung-Ta; Weng, Shao-Ju; Chen, Chien-Fu F.; Huang, Yuahn-Sieh; Chueh, Sheau-Huei; Liao, Mei-Hsiu; Chang, Kang-Wei; Sung, Chi-Chang; Hsu, Te-Hung; Huang, Wen-Sheng; Cheng, Cheng-Yi

    2016-01-01

    3,4-Methylenedioxymethamphetamine (MDMA), a common recreational drug, is known to cause serotonergic neurotoxicity in the brain. Dextromethorphan (DM) is a widely used antitussive reported to exert anti-inflammatory effect in vivo. In this study, we examined the long-term effect of MDMA on the primate serotonergic system and the protective property of DM against MDMA-induced serotonergic abnormality using single photon emission computed tomography (SPECT). Nine monkeys (Macaca cyclopis) were divided into three groups, namely control, MDMA and co-treatment (MDMA/DM). [123I]-ADAM was used as the radioligand for serotonin transporters (SERT) in SPECT scans. SERT levels of the brain were evaluated and presented as the uptake ratios (URs) of [123I]-ADAM in several regions of interest of the brain including midbrain, thalamus and striatum. We found that the URs of [123I]-ADAM were significantly lower in the brains of MDMA than control group, indicating lower brain SERT levels in the MDMA-treated monkeys. This MDMA-induced decrease in brain SERT levels could persist for over four years. However, the loss of brain SERT levels was not observed in co-treatment group. These results suggest that DM may exert a protective effect against MDMA-induced serotonergic toxicity in the brains of the non-human primate. PMID:27941910

  6. Low dose dextromethorphan attenuates moderate experimental autoimmune encephalomyelitis by inhibiting NOX2 and reducing peripheral immune cells infiltration in the spinal cord

    PubMed Central

    Chechneva, Olga V.; Mayrhofer, Florian; Daugherty, Daniel J.; Pleasure, David E.; Hong, Jau-Shyong; Deng, Wenbin

    2011-01-01

    Dextromethorphan (DM) is a dextrorotary morphinan and a widely used component of cough medicine. Relatively high doses of DM in combination with quinidine are used for the treatment of mood disorders for patients with multiple sclerosis (MS). However, at lower doses, morphinans exert anti-inflammatory activities through the inhibition of NOX2-dependent superoxide production in activated microglia. Here we investigated the effects of high (10 mg/kg, i.p., “DM-10”) and low (0.1 mg/kg, i.p., “DM-0.1”) doses of DM on the development and progression of mouse experimental autoimmune encephalomyelitis (EAE), an animal model of MS. We found no protection by high dose DM treatment. Interestingly, a minor late attenuation by low dose DM treatment was seen in severe EAE that was characterized by a chronic disease course and a massive spinal cord infiltration of CD45+ cells including T-lymphocytes, macrophages and neutrophils. Furthermore, in a less severe form of EAE, where lower levels of CD4+ and CD8+ T-cells, Iba1+ microglia/macrophages and no significant infiltration of neutrophils were seen in the spinal cord, the treatment with DM-0.1 was remarkably more beneficial. The effect was the most significant at the peak of disease and was associated with an inhibition of NOX2 expression and a decrease in infiltration of monocytes and lymphocytes into the spinal cord. In addition, chronic treatment with low dose DM resulted in decreased demyelination and reduced axonal loss in the lumbar spinal cord. Our study is the first report to show that low dose DM is effective in treating EAE of moderate severity. Our findings reveal that low dose morphinan DM treatment may represent a new promising protective strategy for treating MS. PMID:21704706

  7. Analysis of dextromethorphan and dextrorphan in decomposed skeletal tissues by microwave assisted extraction, microplate solid-phase extraction and gas chromatography- mass spectrometry (MAE-MPSPE-GCMS).

    PubMed

    Fraser, Candice D; Cornthwaite, Heather M; Watterson, James H

    2015-08-01

    Analysis of decomposed skeletal tissues for dextromethorphan (DXM) and dextrorphan (DXT) using microwave assisted extraction (MAE), microplate solid-phase extraction (MPSPE) and gas chromatography-mass spectrometry (GC-MS) is described. Rats (n = 3) received 100 mg/kg DXM (i.p.) and were euthanized by CO2 asphyxiation roughly 20 min post-dose. Remains decomposed to skeleton outdoors and vertebral bones were recovered, cleaned, and pulverized. Pulverized bone underwent MAE using methanol as an extraction solvent in a closed microwave system, followed by MPSPE and GC-MS. Analyte stability under MAE conditions was assessed and found to be stable for at least 60 min irradiation time. The majority (>90%) of each analyte was recovered after 15 min. The MPSPE-GCMS method was fit to a quadratic response (R(2)  > 0.99), over the concentration range 10-10 000 ng⋅mL(-1) , with coefficients of variation <20% in triplicate analysis. The MPSPE-GCMS method displayed a limit of detection of 10 ng⋅mL(-1) for both analytes. Following MAE for 60 min (80 °C, 1200 W), MPSPE-GCMS analysis of vertebral bone of DXM-exposed rats detected both analytes in all samples (DXM: 0.9-1.5 µg⋅g(-1) ; DXT: 0.5-1.8 µg⋅g(-1) ). Copyright © 2014 John Wiley & Sons, Ltd.

  8. The common antitussive agent dextromethorphan protects against hyperoxia-induced cell death in established in vivo and in vitro models of neonatal brain injury.

    PubMed

    Posod, A; Pinzer, K; Urbanek, M; Wegleiter, K; Keller, M; Kiechl-Kohlendorfer, U; Griesmaier, E

    2014-08-22

    Preterm infants are prematurely subjected to relatively high oxygen concentrations, even when supplemental oxygen is not administered. There is increasing evidence to show that an excess of oxygen is toxic to the developing brain. Dextromethorphan (DM), a frequently used antitussive agent with pleiotropic mechanisms of action, has been shown to be neuroprotective in various models of central nervous system pathology. Due to its numerous beneficial properties, it might also be able to counteract detrimental effects of a neonatal oxygen insult. The aim of the current study was to evaluate its therapeutic potential in established cell culture and rodent models of hyperoxia-induced neonatal brain injury. For in vitro studies pre- and immature oligodendroglial (OLN-93) cells were subjected to hyperoxic conditions for 48 h after pre-treatment with increasing doses of DM. For in vivo studies 6-day-old Wistar rat pups received a single intraperitoneal injection of DM in two different dosages prior to being exposed to hyperoxia for 24h. Cell viability and caspase-3 activation were assessed as outcome parameters at the end of exposure. DM significantly increased cell viability in immature oligodendroglial cells subjected to hyperoxia. In pre-oligodendroglial cells cell viability was not significantly affected by DM treatment. In vivo caspase-3 activation induced by hyperoxic exposure was significantly lower after administration of DM in gray and white matter areas. In control animals kept under normoxic conditions DM did not significantly influence caspase-3-dependent apoptosis. The present results indicate that DM is a promising and safe treatment strategy for neonatal hyperoxia-induced brain injury that merits further investigation. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  9. Physiologically based modelling of inhibition of metabolism and assessment of the relative potency of drug and metabolite: dextromethorphan vs. dextrorphan using quinidine inhibition

    PubMed Central

    Moghadamnia, A A; Rostami-Hodjegan, A; Abdul-Manap, R; Wright, C E; Morice, A H; Tucker, G T

    2003-01-01

    Aims To define the relative antitussive effect of dextromethorphan (DEX) and its primary metabolite dextrorphan (DOR) after administration of DEX. Methods Data were analysed from a double-blind, randomized cross-over study in which 22 subjects received the following oral treatments: (i) placebo; (ii) 30 mg DEX hydro-bromide; (iii) 60 mg DEX hydro-bromide; and (iv) 30 mg DEX hydro-bromide preceded at 1 h by quinidine HCl (50 mg). Cough was elicited using citric acid challenge. Pharmacokinetic data from all non-placebo arms of the study were fitted simultaneously. The parameters were then used as covariates in a link PK–PD model of cough suppression using data from all treatment arms. Results The best-fit PK model assumed two- and one-compartment PK models for DEX and DOR, respectively, and competitive inhibition of DEX metabolism by quinidine. The intrinsic clearance of DEX estimated from the model ranged from 59 to 1536 l h−1, which overlapped with that extrapolated from in vitro data (12–261 l h−1) and showed similar variation (26- vs. 21-fold, respectively). The inhibitory effect of quinidine ([I]/Ki) was 19 (95% confidence interval of mean: 18–20) with an estimated average Ki of 0.017 µM. Although DEX and DOR were both active, the potency of the antitussive effect of DOR was 38% that of DEX. A sustained antitussive effect was related to slow removal of DEX/DOR from the effect site (ke0 = 0.07 h−1). Conclusions Physiologically based PK modelling with perturbation of metabolism using an inhibitor allowed evaluation of the antitussive potency of DOR without the need for separate administration of DOR. PMID:12848776

  10. Role of hypothermia in the mechanism of protection against serotonergic toxicity. II. Experiments with methamphetamine, p-chloroamphetamine, fenfluramine, dizocilpine and dextromethorphan.

    PubMed

    Farfel, G M; Seiden, L S

    1995-02-01

    Several amphetamine analogs, when administered in high-dose regimens, have been shown to cause long-lasting depletions of central serotonin (5-HT), which are indicative of neuronal toxicity. These depletions and the resulting toxicity can be attenuated pharmacologically or by lowering ambient temperature. The noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (DZ) blocks depletion of 5-HT induced by methamphetamine (METH) and p-chloroamphetamine (PCA), but not fenfluramine (FEN). This study investigated whether the effects of DZ and another calcium channel antagonist, dextromethorphan (DEX), are due to induction of hypothermia. Male Sprague-Dawley rats were injected with either saline (SAL), DZ (1 or 2 injections of 2.5 mg/kg), or DEX (75.0 mg/kg) followed by either SAL, METH (4 injections of 10.0 mg/kg), PCA (1 injection of 10.0 mg/kg) or FEN (2 or 4 injections of 12.5 mg/kg). Core body temperature (TEMP) was monitored for 4 h or longer with radiotelemetry. Base-line TEMP was between 37.0 and 37.6 degrees C. SAL/METH caused a significant increase in TEMP which peaked at 40.8 +/- 0.50 degrees C after the last injection. Coadministration of DZ with METH caused TEMP to decrease to 33.8 +/- 0.30 degrees C within 2 h of the first injection and lasting more than 3 h, and protected against depletion of 5-HT. SAL/PCA caused a small increase in TEMP to 37.7 +/- 0.36 degrees C, whereas coadministration of DZ with PCA decreased TEMP to 35.2 +/- 0.50 degrees C, lasting 2 h, in a dose regimen which has been shown to be neuroprotective.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. An open-label multicenter study to assess the safety of dextromethorphan/quinidine in patients with pseudobulbar affect associated with a range of underlying neurological conditions.

    PubMed

    Pattee, Gary L; Wymer, James P; Lomen-Hoerth, Catherine; Appel, Stanley H; Formella, Andrea E; Pope, Laura E

    2014-11-01

    Pseudobulbar affect (PBA) is associated with neurological disorders or injury affecting the brain, and characterized by frequent, uncontrollable episodes of crying and/or laughing that are exaggerated or unrelated to the patient's emotional state. Clinical trials establishing dextromethorphan and quinidine (DM/Q) as PBA treatment were conducted in patients with amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS). This trial evaluated DM/Q safety in patients with PBA secondary to any neurological condition affecting the brain. To evaluate the safety and tolerability of DM/Q during long-term administration to patients with PBA associated with multiple neurological conditions. Fifty-two-week open-label study of DM/Q 30/30 mg twice daily. Safety measures included adverse events (AEs), laboratory tests, electrocardiograms (ECGs), vital signs, and physical examinations. #NCT00056524. A total of 553 PBA patients with >30 different neurological conditions enrolled; 296 (53.5%) completed. The most frequently reported treatment-related AEs (TRAEs) were nausea (11.8%), dizziness (10.5%), headache (9.9%), somnolence (7.2%), fatigue (7.1%), diarrhea (6.5%), and dry mouth (5.1%). TRAEs were mostly mild/moderate, generally transient, and consistent with previous controlled trials. Serious AEs (SAEs) were reported in 126 patients (22.8%), including 47 deaths, mostly due to ALS progression and respiratory failure. No SAEs were deemed related to DM/Q treatment by investigators. ECG results suggested no clinically meaningful effect of DM/Q on myocardial repolarization. Differences in AEs across neurological disease groups appeared consistent with the known morbidity of the primary neurological conditions. Study interpretation is limited by the small size of some disease groups, the lack of a specific efficacy measure and the use of a DM/Q dose higher than the eventually approved dose. DM/Q was generally well tolerated over this 52 week trial in patients with PBA

  12. An open-label multicenter study to assess the safety of dextromethorphan/quinidine in patients with pseudobulbar affect associated with a range of underlying neurological conditions

    PubMed Central

    Pattee, Gary L.; Wymer, James P.; Lomen-Hoerth, Catherine; Appel, Stanley H.; Formella, Andrea E.; Pope, Laura E.

    2014-01-01

    Abstract Background: Pseudobulbar affect (PBA) is associated with neurological disorders or injury affecting the brain, and characterized by frequent, uncontrollable episodes of crying and/or laughing that are exaggerated or unrelated to the patient’s emotional state. Clinical trials establishing dextromethorphan and quinidine (DM/Q) as PBA treatment were conducted in patients with amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS). This trial evaluated DM/Q safety in patients with PBA secondary to any neurological condition affecting the brain. Objective: To evaluate the safety and tolerability of DM/Q during long-term administration to patients with PBA associated with multiple neurological conditions. Methods: Fifty-two-week open-label study of DM/Q 30/30 mg twice daily. Safety measures included adverse events (AEs), laboratory tests, electrocardiograms (ECGs), vital signs, and physical examinations. Clinical trial registration: #NCT00056524. Results: A total of 553 PBA patients with >30 different neurological conditions enrolled; 296 (53.5%) completed. The most frequently reported treatment-related AEs (TRAEs) were nausea (11.8%), dizziness (10.5%), headache (9.9%), somnolence (7.2%), fatigue (7.1%), diarrhea (6.5%), and dry mouth (5.1%). TRAEs were mostly mild/moderate, generally transient, and consistent with previous controlled trials. Serious AEs (SAEs) were reported in 126 patients (22.8%), including 47 deaths, mostly due to ALS progression and respiratory failure. No SAEs were deemed related to DM/Q treatment by investigators. ECG results suggested no clinically meaningful effect of DM/Q on myocardial repolarization. Differences in AEs across neurological disease groups appeared consistent with the known morbidity of the primary neurological conditions. Study interpretation is limited by the small size of some disease groups, the lack of a specific efficacy measure and the use of a DM/Q dose higher than the eventually approved dose

  13. Multivariate optimization and validation of a capillary electrophoresis method for the simultaneous determination of dextromethorphan hydrobromur, phenylephrine hydrochloride, paracetamol and chlorpheniramine maleate in a pharmaceutical preparation using response surface methodology.

    PubMed

    Palabiyik, I Murat; Onur, Feyyaz

    2010-01-01

    A fast, accurate, precise and sensitive capillary electrophoresis method for the simultaneous determination of dextromethorphan hydrobromide, phenylephrine hydrochloride, paracetamol and chlorpheniramine maleate has been developed. Response surface methodology with a central composite design was used for optimization of the concentration of the buffer, pH of the buffer and applied voltage. Therefore, working with Na(2)HPO(4) buffer (pH 8.00, 0.01 M) at 20 kV as an applied voltage in the capillary electrophoresis method were found to be suitable; under these optimal conditions, these four active ingredients were separated in about 7 min. This developed method was validated and successfully applied to a pharmaceutical preparation, sugar-coated tablet, and the results were compared with a high-performance liquid chromatographic method developed by us.

  14. Development and validation of a sensitive UHPLC-MS/MS method for the simultaneous analysis of tramadol, dextromethorphan chlorpheniramine and their major metabolites in human plasma in forensic context: application to pharmacokinetics.

    PubMed

    Heneedak, Hala M; Salama, Ismail; Mostafa, Samia; El-Kady, Ehab; El-Sadek, Mohamed

    2015-07-01

    The prerequisites for forensic confirmatory analysis by LC/MS/MS with respect to European Union guidelines are chromatographic separation, a minimum number of two MS/MS transitions to obtain the required identification points and predefined thresholds for the variability of the relative intensities of the MS/MS transitions (MRM transitions) in samples and reference standards. In the present study, a fast, sensitive and robust method to quantify tramadol, chlorpheniramine, dextromethorphan and their major metabolites, O-desmethyltramadol, dsmethyl-chlorpheniramine and dextrophan, respectively, in human plasma using ibuprofen as internal standard (IS) is described. The analytes and the IS were extracted from plasma by a liquid-liquid extraction method using ethyl acetate-diethyl-ether (1:1). Extracted samples were analyzed by ultra-high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS). Chromatographic separation was performed by pumping the mobile phase containing acetonitrile, water and formic acid (89.2:11.7:0.1) for 2.0 min at a flow rate of 0.25 μL/min into a Hypersil-Gold C18 column, 20 × 2.0 mm (1.9 µm) from Thermoscientific, New York, USA. The calibration curve was linear for the six analytes. The intraday precision (RSD) and accuracy (RE) of the method were 3-9.8 and -1.7-4.5%, respectively. The analytical procedure herein described was used to assess the pharmacokinetics of the analytes in 24 healthy volunteers after a single oral dose containing 50 mg of tramadol hydrochloride, 3 mg chlorpheniramine maleate and 15 mg of dextromethorphan hydrobromide.

  15. PRISM II: an open-label study to assess effectiveness of dextromethorphan/quinidine for pseudobulbar affect in patients with dementia, stroke or traumatic brain injury.

    PubMed

    Hammond, Flora M; Alexander, David N; Cutler, Andrew J; D'Amico, Stephen; Doody, Rachelle S; Sauve, William; Zorowitz, Richard D; Davis, Charles S; Shin, Paul; Ledon, Fred; Yonan, Charles; Formella, Andrea E; Siffert, Joao

    2016-06-09

    Phase 3 trials supporting dextromethorphan/quinidine (DM/Q) use as a treatment for pseudobulbar affect (PBA) were conducted in patients with amyotrophic lateral sclerosis (ALS) or multiple sclerosis (MS). The PRISM II study provides additional DM/Q experience with PBA secondary to dementia, stroke, or traumatic brain injury (TBI). Participants in this open-label, multicenter, 90-day trial received DM/Q 20/10 mg twice daily. The primary outcome was the Center for Neurologic Study-Lability Scale (CNS-LS), assessing change in PBA episode frequency and severity. The CNS-LS final visit score was compared to baseline (primary analysis) and to the response in a previously conducted placebo-controlled trial with DM/Q in patients with ALS or MS. Secondary outcomes included change in PBA episode count and Clinical Global Impression of Change with respect to PBA as rated by a clinician (CGI-C) and by the patient or caregiver (PGI-C). The study enrolled 367 participants with PBA secondary to dementia, stroke, or TBI. Mean (standard deviation [SD]) CNS-LS score improved significantly from 20.4 (4.4) at baseline to 12.8 (5.0) at Day 90/Final Visit (change, -7.7 [6.1]; P < .001, 95 % CI: -8.4, -7.0). This magnitude of improvement was consistent with DM/Q improvement in the earlier phase-3, placebo-controlled trial (mean [95 % CI] change from baseline, -8.2 [-9.4, -7.0]) and numerically exceeds the improvement seen with placebo in that study (-5.7 [-6.8, -4.7]). Reduction in PBA episode count was 72.3 % at Day 90/Final Visit compared with baseline (P < .001). Scores on CGI-C and PGI-C showed that 76.6 and 72.4 % of participants, respectively, were "much" or "very much" improved with respect to PBA. The most frequently occurring adverse events (AEs) were diarrhea (5.4 %), headache (4.1 %), urinary tract infection (2.7 %), and dizziness (2.5 %); 9.8 % had AEs that led to discontinuation. Serious AEs were reported in 6.3 %; however, none were considered treatment

  16. Dextromethorphan Distribution Act of 2009

    THOMAS, 111th Congress

    Rep. Upton, Fred [R-MI-6

    2009-03-03

    04/01/2009 Received in the Senate and Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

  17. Dextromethorphan Distribution Act of 2009

    THOMAS, 111th Congress

    Rep. Upton, Fred [R-MI-6

    2009-03-03

    04/01/2009 Received in the Senate and Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

  18. Dextromethorphan Distribution Act of 2009

    THOMAS, 111th Congress

    Rep. Upton, Fred [R-MI-6

    2009-03-03

    Senate - 04/01/2009 Received in the Senate and Read twice and referred to the Committee on Health, Education, Labor, and Pensions. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

  19. Potential mechanism of action of 3'-demethoxy-6-O-demethyl-isoguaiacin on methicillin resistant Staphylococcus aureus.

    PubMed

    Favela-Hernández, Juan Manuel J; Clemente-Soto, Aldo F; Balderas-Rentería, Isaías; Garza-González, Elvira; Camacho-Corona, María Del Rayo

    2015-07-08

    Bacterial infections represent one of the main threats to global public health. One of the major causative agents associated with high morbidity and mortality infections in hospitals worldwide is methicillin-resistant Staphylococcus aureus. Therefore, there is a need to develop new antibacterial agents to treat these infections, and natural products are a rich source of them. In previous studies, we reported that lignan 3'-demethoxy-6-O-demethylisoguaiacin, isolated and characterized from Larrea tridentate, showed the best activity towards methicillin-resistant S. aureus. Thus, the aim of this study was to determine the potential molecular mechanism of the antibacterial activity of 3'-demethoxy-6-O-demethylisoguaiacin against methicillin-resistant S. aureus using microarray technology. Results of microarray genome expression were validated by real-time polymerase chain reaction (RT-PCR). The genetic profile expression results showed that lignan 3'-demethoxy-6-O-demethylisoguaiacin had activity on cell membrane affecting proteins of the ATP-binding cassette (ABC) transport system causing bacteria death. This molecular mechanism is not present in any antibacterial commercial drug and could be a new target for the development of novel antibacterial agents.

  20. Potential Mechanism of Action of 3'-Demethoxy-6-O-demethyl-isoguaiacin on Methicillin Resistant Staphylococcus aureus.

    PubMed

    Favela-Hernández, Juan Manuel J; Clemente-Soto, Aldo F; Balderas-Rentería, Isaías; Garza-González, Elvira; Camacho-Corona, María del Rayo

    2015-07-08

    Bacterial infections represent one of the main threats to global public health. One of the major causative agents associated with high morbidity and mortality infections in hospitals worldwide is methicillin-resistant Staphylococcus aureus. Therefore, there is a need to develop new antibacterial agents to treat these infections, and natural products are a rich source of them. In previous studies, we reported that lignan 3'-demethoxy-6-O-demethylisoguaiacin, isolated and characterized from Larrea tridentate, showed the best activity towards methicillin-resistant S. aureus. Thus, the aim of this study was to determine the potential molecular mechanism of the antibacterial activity of 3'-demethoxy-6-O-demethylisoguaiacin against methicillin-resistant S. aureus using microarray technology. Results of microarray genome expression were validated by real-time polymerase chain reaction (RT-PCR). The genetic profile expression results showed that lignan 3'-demethoxy-6-O-demethylisoguaiacin had activity on cell membrane affecting proteins of the ATP-binding cassette (ABC) transport system causing bacteria death. This molecular mechanism is not present in any antibacterial commercial drug and could be a new target for the development of novel antibacterial agents.

  1. Effects of dextromethorphan as add-on to sitagliptin on blood glucose and serum insulin concentrations in individuals with type 2 diabetes mellitus: a randomized, placebo-controlled, double-blinded, multiple crossover, single-dose clinical trial.

    PubMed

    Marquard, J; Stirban, A; Schliess, F; Sievers, F; Welters, A; Otter, S; Fischer, A; Wnendt, S; Meissner, T; Heise, T; Lammert, E

    2016-01-01

    In this clinical trial, we investigated the blood glucose (BG)-lowering effects of 30, 60 and 90 mg dextromethorphan (DXM) as well as 100 mg sitagliptin alone versus combinations of DXM and sitagliptin during an oral glucose tolerance test (OGTT) in 20 men with T2DM. The combination of 60 mg DXM plus 100 mg sitagliptin was observed to have the strongest effect in the OGTT. It lowered maximum BG concentrations and increased the baseline-adjusted area under the curve for serum insulin concentrations in the first 30 min of the OGTT (mean ± standard deviation 240 ± 47 mg/dl and 8.1 ± 6.1 mU/l/h, respectively) to a significantly larger extent than did 100 mg sitagliptin alone (254 ± 50 mg/dl and 5.8 ± 2.5 mU/l/h, respectively; p < 0.05) and placebo (272 ± 49 mg/dl and 3.9 ± 3.0 mU/l/h, respectively; p < 0.001). All study drugs were well tolerated, alone and in combination, without serious adverse events or hypoglycaemia. Long-term clinical trials are now warranted to investigate the potential of the combination of 30 or 60 mg DXM and dipeptidyl peptidase-4 inhibitors in the treatment of individuals with T2DM, in particular as preclinical studies have identified the β-cell protective properties of DXM.

  2. On-line solid phase extraction using the Prospekt-2 coupled with a liquid chromatography/tandem mass spectrometer for the determination of dextromethorphan, dextrorphan and guaifenesin in human plasma.

    PubMed

    Kuhlenbeck, Debbie L; Eichold, Thomas H; Hoke, Steven H; Baker, Timothy R; Mensen, Robert; Wehmeyer, Kenneth R

    2005-01-01

    An on-line liquid chromatography/tandem mass spectrometry (LC-MS/MS) procedure, using the Prospekt- 2 system, was developed and used for the determination of the levels of the active ingredients of cough/cold medications in human plasma matrix. The experimental configuration allows direct plasma injection by performing on- line solid phase extraction (SPE) on small cartridge columns prior to elution of the analyte(s) onto the analytical column and subsequent MS/MS detection. The quantitative analysis of three analytes with differing polarities, dextromethorphan (DEX), dextrorphan (DET) and guaifenesin (GG) in human plasma presented a significant challenge. Using stable-isotope-labeled internal standards for each analyte, the Prospekt-2 on-line methodology was evaluated for sensitivity, suppression, accuracy, precision, linearity, analyst time, analysis time, cost, carryover and ease of use. The lower limit of quantitation for the on-line SPE procedure for DEX, DET and GG was 0.05, 0.05 and 5.0 ng mL(-1), respectively, using a 0.1 mL sample volume. The linear range for DEX and DET was 0.05-50 ng mL(-1) and was 5-5,000 ng mL(-1) for GG. Accuracy and precision data for five different levels of QC samples were collected over three separate days. Accuracy ranged from 90% to 112% for all three analytes, while the precision, as measured by the %RSD, ranged from 1.5% to 16.0%

  3. Pharmacogenetic determination of the effects of codeine and prediction of drug interactions.

    PubMed

    Caraco, Y; Sheller, J; Wood, A J

    1996-09-01

    To define the differences in codeine pharmacodynamics in extensive (EMs) and poor (PMs) metabolizers of debrisoquin and to determine whether the inhibition of codeine's metabolism by quinidine produces phenotypically dependent pharmacodynamic changes, we studied 16 healthy nonsmoking males, 10 EMs and 6 PMs of debrisoquin. The subjects received in random double-blind fashion 120 mg of codeine plus placebo, 120 mg of codeine plus 100 mg of quinidine and 100 mg of quinidine plus placebo. Blood was obtained over 24 hr and urine was collected for 48 hr. Respiratory, psychomotor and pupillary effects of codeine were greater in the EMs than in the PMs (P < .01). Morphine and morphine metabolites were detectable only in plasma from EMs. Codeine metabolic clearance by O-demethylation was almost 200-fold greater in the EMs than in the PMs. After coadministration of quinidine, morphine and morphine metabolites were not detectable in the plasma of either phenotype and mean (+/- S.E.M.) O-demethylation clearance was reduced in the EMs from 162.7 +/- 36.6 to 17.0 +/- 5.0 ml/min (P < .003), but not in the PMs. The diminished production of morphine in the EMs was associated with significantly reduced respiratory, psychomotor and pupillary effects (P < .01). Thus, CYP2D6 mediated O-demethylation of codeine to morphine is central to its pharmacodynamic effects. Patients who lack CYP2D6 or whose CYP2D6 is inhibited would not be expected to benefit from codeine. Thus, phenotyping for CYP2D6 and the avoidance of CYP2D6 inhibitors is justified in patients with chronic path before initiating long-term therapy with analgesics whose in vivo activation is dependent on CYP2D6 activity (i.e., codeine, hydrocodone and oxycodone.

  4. Selective inhibition of the cytochrome P450 isoform by hyperoside and its potent inhibition of CYP2D6.

    PubMed

    Song, Min; Hong, Miri; Lee, Min Young; Jee, Jun-Goo; Lee, You Mie; Bae, Jong-Sup; Jeong, Tae Cheon; Lee, Sangkyu

    2013-09-01

    Hyperoside, quercetin-3-O-galactoside, is a flavonoid isolated from Oenanthe javanica. In the present study, we investigated potential herb-drug inhibitory effects of hyperoside on nine cytochrome P450 (CYP) isoforms in pooled human liver microsomes (HLMs) and human recombinant cDNA expressed CYP using a cocktail probe assay. Hyperoside strongly inhibited CYP2D6-catalyzed dextromethorphan O-demethylation, with IC₅₀ values of 1.2 and 0.81 μM after 0 and 15 min of preincubation, and a Ki value of 2.01 μM in HLMs, respectively. Hyperoside strongly decreased CYP2D6 activity dose-, but not time-, dependently in HLMs. In addition, the Lineweaver-Burk and Secondary plots for the inhibition of CYP2D6 in HLMs fitted a competitive inhibition mode. Furthermore, hyperoside decreased CYP2D6-catalyzed dextromethorphan O-demethylation activity of human recombinant cDNA-expressed CYP2D6, with an IC₅₀ value of 3.87 μM. However, other CYPs were not inhibited significantly by hyperoside. In conclusion, our data demonstrate that hyperoside is a potent selective CYP2D6 inhibitor in HLMs, and suggest that hyperoside might cause herb-drug interactions when co-administrated with CYP2D substrates.

  5. Combination With Low-dose Dextromethorphan Improves the Effect of Amlodipine Monotherapy in Clinical Hypertension: A First-in-human, Concept-proven, Prospective, Dose-escalation, Multicenter Study.

    PubMed

    Yin, Wei-Hsian; Chen, Pei; Yeh, Hung-I; Wang, Kuo-Yang; Hung, Yi-Jen; Tseng, Wei-Kung; Wen, Ming-Shien; Wu, Tao-Cheng; Wu, Chau-Chung; Cheng, Shu-Meng; Chen, Jaw-Wen

    2016-03-01

    The combination of low rather than high dose of dextromethorphan (DXM) with amlodipine (AM) could improve blood pressure (BP) reduction in hypertensive animals. The study aimed to evaluate the feasibility of different doses of DXM combined with standard AM treatment in clinical hypertension.This was a prospective, 14-week, dose-escalation, multicenter study. After 2-week run-in period with AM 5 mg/day, hypertensive patients who got the BP goal of 140/90 mmHg kept receiving AM monotherapy for another 12 weeks. The nonresponders, while kept on AM 5 mg/day, received additional DXM treatment for 3 sequential dose-titrated periods with initially 2.5 mg/day, followed by 7.5 mg/day, and finally 30 mg/day. Each period was for 4 weeks. The patients at BP goal after each treatment period were defined as the responders and kept on the same combination till the end of the study. The responder rate of each treatment period was recorded. The changes of BP and serum antioxidant/endothelial markers between week 14 and week 2 were evaluated.Of the 103 patients initially enrolled, 89 entered the treatment period. In the 78 patients completing the study, 31 (40%) at BP goal after 2-week AM run-in kept on AM monotherapy (DXM0). The addition of 2.5 (DXM2.5) and 7.5 mg/day (DXM7.5) of DXM enabled BP goal achievement in 22 (47%) nonresponders to AM monotherapy including 16 (29%) with DXM2.5 and 6 (18%) with DXM7.5. Only 4 patients (16%) reached BP goal with the combination of DXM 30 mg/day (DXM30). Overall, 73% of the 78 patients reached BP goal at the end of the 14-week study. Mean systolic BP was reduced by 7.9% ± 7.0% with DXM2.5 (P < 0.001) and by 5.4% ± 2.4% with DXM7.5 (P = 0.003) respectively at week 14 from that at week 2, which was unchanged in either DXM0 or DXM30 group. Besides, the effects of combination treatment were particularly significant in the patients with impaired endothelial function suggested by reduced serum NOx level at baseline

  6. Dextromethorphan Abuse Reduction Act of 2009

    THOMAS, 111th Congress

    Sen. Durbin, Richard [D-IL

    2009-06-25

    06/25/2009 Read twice and referred to the Committee on the Judiciary. (text of measure as introduced: CR S7098-7099) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  7. Methadone inhibits CYP2D6 and UGT2B7/2B4 in vivo: a study using codeine in methadone- and buprenorphine-maintained subjects

    PubMed Central

    Gelston, Eloise A; Coller, Janet K; Lopatko, Olga V; James, Heather M; Schmidt, Helmut; White, Jason M; Somogyi, Andrew A

    2012-01-01

    AIMS To compare the O-demethylation (CYP2D6-mediated), N-demethylation (CYP3A4-mediated) and 6-glucuronidation (UGT2B4/7-mediated) metabolism of codeine between methadone- and buprenorphine-maintained CYP2D6 extensive metabolizer subjects. METHODS Ten methadone- and eight buprenorphine-maintained subjects received a single 60 mg dose of codeine phosphate. Blood was collected at 3 h and urine over 6 h and assayed for codeine, norcodeine, morphine, morphine-3- and -6-glucuronides and codeine-6-glucuronide. RESULTS The urinary metabolic ratio for O-demethylation was significantly higher (P = 0.0044) in the subjects taking methadone (mean ± SD, 2.8 ± 3.1) compared with those taking buprenorphine (0.60 ± 0.43), likewise for 6-glucuronide formation (0.31 ± 0.24 vs. 0.053 ± 0.027; P < 0.0002), but there was no significant difference (P = 0.36) in N-demethylation. Similar changes in plasma metabolic ratios were also found. In plasma, compared with those maintained on buprenorphine, the methadone-maintained subjects had increased codeine and norcodeine concentrations (P < 0.004), similar morphine (P = 0.72) and lower morphine-3- and -6- and codeine-6-glucuronide concentrations (P < 0.008). CONCLUSION Methadone is associated with inhibition of CYP2D6 and UGTs 2B4 and 2B7 reactions in vivo, even though it is not a substrate for these enzymes. Plasma morphine was not altered, owing to the opposing effects of inhibition of both formation and elimination; however, morphine-6-glucuronide (analgesically active) concentrations were substantially reduced. Drug interactions with methadone are likely to include drugs metabolized by various UGTs and CYP2D6. PMID:22092298

  8. Appetite suppressant drugs as inhibitors of human cytochromes P450: in vitro inhibition of P450-2D6 by D- and L-fenfluramine, but not phentermine.

    PubMed

    von Moltke, L L; Greenblatt, D J; Ciraulo, D A; Grassi, J M; Granda, B W; Duan, S X; Harmatz, J S; Shader, R I

    1998-08-01

    The activity of D-fenfluramine, L-fenfluramine, and phentermine as inhibitors of five human cytochromes P450 was evaluated using human liver microsomes in vitro. All three compounds produced negligible inhibition of P450-1A2, -2C9, -2E1, and -3A. Phentermine also did not inhibit P450-2D6. However, D- and L-fenfluramine significantly inhibited P450-2D6 activity as measured by dextromethorphan O-demethylation, with mean 50% inhibitory concentrations (15.1 microM) within one order of magnitude of that for fluoxetine (2.7 microM). Findings from the in vitro assay are consistent with clinical studies showing significant inhibition of desipramine clearance by coadministration of fenfluramine.

  9. Rapid and accurate liquid chromatography and tandem mass spectrometry method for the simultaneous quantification of ten metabolic reactions catalyzed by hepatic cytochrome P450 enzymes.

    PubMed

    Shi, Rong; Ma, Bingliang; Wu, Jiasheng; Wang, Tianming; Ma, Yueming

    2015-10-01

    The hepatic cytochrome P450 enzymes play a central role in the biotransformation of endogenous and exogenous substances. A sensitive high-throughput liquid chromatography with tandem mass spectrometry assay was developed and validated for the simultaneous quantification of the products of ten metabolic reactions catalyzed by hepatic cytochrome P450 enzymes. After the substrates were incubated separately, the samples were pooled and analyzed by liquid chromatography with tandem mass spectrometry using an electrospray ionization source in the positive and negative ion modes. The method exhibited linearity over a broad concentration range, insensitivity to matrix effects, and high accuracy, precision, and stability. The novel method was successfully applied to study the kinetics of phenacetin-O deethylation, coumarin-7 hydroxylation, bupropion hydroxylation, taxol-6 hydroxylation, omeprazole-5 hydroxylation, dextromethorphan-O demethylation, tolbutamide-4 hydroxylation, chlorzoxazone-6 hydroxylation, testosterone-6β hydroxylation, and midazolam-1 hydroxylation in rat liver microsomes.

  10. The inhibitory effect of tannic acid on cytochrome P450 enzymes and NADPH-CYP reductase in rat and human liver microsomes.

    PubMed

    Yao, Hsien-Tsung; Chang, Yi-Wei; Lan, Shih-Jung; Yeh, Teng-Kuang

    2008-02-01

    Tannic acid has been shown to decrease mutagenicity and/or carcinogenicity of several amine derivatives and polycyclic aromatic hydrocarbons in rodents. The purpose of this study was to evaluate the effect of tannic acid on cytochrome P450 (CYP)-catalyzed oxidations using rat liver microsomes (RLM) and human liver microsomes (HLM) as the enzyme sources. In RLM, tannic acid showed a non-selective inhibitory effect on 7-methoxyresorufin O-demethylation (MROD), 7-ethoxyresorufin O-deethylation (EROD), tolbutamide hydroxylation, p-nitrophenol hydroxylation and testosterone 6beta-hydroxylation activities with IC(50) values ranged from 14.9 to 27.4 microM. In HLM, tannic acid inhibited EROD, MROD and phenacetin O-deethylation activities with IC(50) values ranged from 5.1 to 7.5 microM, and diclofenac 4-hydroxylation, dextromethorphan O-demethylation, chlorzoxazone 6-hydroxylation and testosterone 6beta-hydroxylation with IC(50) values ranged from 20 to 77 microM. In baculovirus-insect cell-expressed human CYP 1A1 and 1A2, the IC(50) values of tannic acid for CYP 1A1- and 1A2-catalyzed EROD activities were 23.1 and 2.3 microM, respectively, indicating that tannic acid preferably inhibited the activity of CYP1A2. Tannic acid inhibited human CYP1A2 non-competitively with a Ki value of 4.8 microM. Tannic acid was also found to inhibit NADPH-CYP reductase in RLM and HLM with IC(50) values of 11.8 and 17.4 microM, respectively. These results suggested that the inhibition of CYP enzyme activities by tannic acid may be partially attributed to its inhibition of NADPH-CYP reductase activity.

  11. Application of a higher throughput approach to derive apparent Michaelis-Menten constants of isoform-selective p450-mediated biotransformation reactions in human hepatocytes.

    PubMed

    Li, Albert P; Schlicht, Kari E

    2014-01-01

    A higher throughput platform was developed for the determination of K(M) values for isoformselective P450 substrates in human hepatocytes via incubation of the hepatocytes with substrates in 384- well plates and metabolite quantification by RapidFire™ mass spectrometry. Isoform-selective P450 substrates were incubated at 8 concentrations in triplicate with cryopreserved human hepatocytes from 16 donors. The metabolic pathways examined were the CYP1A2-catalyzed tacrine 1-hydroxylation, CYP2B6-catalyzed bupropion hydroxylation, CYP2C8-catalyzed amodiaquine N-deethylation, CYP2C9- catalyzed diclofenac 4'-hydroxylation, CYP2D6-catalyzed dextromethorphan O-demethylation, and CYP3A4-catalyzed midazolam 1'-hydroxylation. Typical saturation enzyme kinetics was observed for all the pathways evaluated. Individual differences in the apparent V(max) and K(M) values were observed among the human hepatocytes from each of the 16 individual donors, with no statistically significant gender- or age-associated differences. A "composite" K(M) value was calculated for each of the pathways via normalizing the individual activities to their respective V(max) values to develop "relative activities" followed by Michaelis-Menten analysis of the mean relative activities of the 16 donors at each of the 8 substrate concentrations. The resulting "composite" K(M) values for the P450 substrates may be used to guide in vitro P450 inhibition and induction studies and kinetic modeling of in vivo drug-drug interaction.

  12. Potent inhibition of yeast-expressed CYP2D6 by dihydroquinidine, quinidine, and its metabolites.

    PubMed

    Ching, M S; Blake, C L; Ghabrial, H; Ellis, S W; Lennard, M S; Tucker, G T; Smallwood, R A

    1995-09-07

    The inhibitory effects of dihydroquinidine, quinidine and several quinidine metabolites on cytochrome P450 2D6 (CYP2D6) activity were examined. CYP2D6 heterologously expressed in yeast cells O-demethylated dextromethorphan with a mean Km of 5.4 microM and a Vmax of 0.47 nmol/min/nmol. Quinidine and dihydroquinidine both potently inhibited CYP2D6 metabolic activity (mean Ki = 0.027 and 0.013 microM, respectively) in yeast microsomes and in human liver microsomes. The metabolites, 3-hydroxyquinidine, O-desmethylquinidine and quinidine N-oxide also inhibited CYP2D6, but their Ki values (0.43 to 2.3 microM) were one to two orders of magnitude weaker than the values for quinidine and dihydroquinidine. There was a trend towards an inverse relationship between Ki and lipophilicity (r = -0.90, N = 5, P = 0.07), as determined by the retention-time parameter k' using reverse-phase HPLC. Thus, although the metabolites of quinidine have the capacity to inhibit CYP2D6 activity, quinidine and the impurity dihydroquinidine are the important inhibitors of CYP2D6.

  13. In vitro metabolism studies of new adenosine A 2A receptor antagonists.

    PubMed

    Marucci, Gabriella; Finaurini, Sara; Buccioni, Michela; Lammi, Carmen; Kandhavelu, Meenakshisundaram; Volpini, Rosaria; Ricciutelli, Massimo; Angeli, Piero; Commandeur, Jan N M; Cristalli, Gloria

    2008-12-01

    Evidence, obtained in rodent and primate models of Parkinson's disease (PD) and in preliminary clinical trials, indicates that adenosine A(2A) receptor antagonists might represent a promising non-dopaminergic therapeutic tool for the treatment of PD. Recently, we have reported the biological evaluation of 8-substituted 9-ethyladenines (ANR) as new A(2A) receptor antagonists, three of which (ANR 82, ANR 94, and ANR 152) showed high efficacy in in vivo models for Parkinson's. Understanding the metabolic pathways of new drug candidates is an important aspect of drug discovery. The ANR compounds have been investigated in order to clarify their activity on rat liver microsomes, and more specifically on recombinant human cytochrome P450 2D6 (CYP2D6). The metabolites of all three compounds were detected by liquid chromatography/tandem mass spectrometry (LC-MS/MS). The results indicate that this class of 9-ethyladenines is metabolized only to a fraction of 1.5-5%. These compounds also act as potent mechanism-based inhibitors of CYP450 and in particular of human isoform CYP2D6. Kinetic-analysis of enzyme inactivation was used to describe the effect of these time-dependent inhibitors and to derive the inhibition parameters K(inact) and K(i) defined with respect to the O-demethylation of dextromethorphan.

  14. CYP2D6 Is Inducible by Endogenous and Exogenous Corticosteroids.

    PubMed

    Farooq, Muhammad; Kelly, Edward J; Unadkat, Jashvant D

    2016-05-01

    Although cytochrome P450 (CYP) 2D6 has been widely considered to be noninducible on the basis of human hepatocyte studies, in vivo data suggests that it is inducible by endo- and xenobiotics. Therefore, we investigated if the experimental conditions routinely used in human hepatocyte studies may be a confounding factor in the lack of in vitro induction of CYP2D6. Sandwich cultured human hepatocytes (SCHH) were preincubated with or without dexamethasone (100 nM) for 72 hours before incubation with 1μM endogenous (cortisol or corticosterone) or exogenous (dexamethasone or prednisolone) corticosteroids. At 72 hours, CYP2D6 mRNA, protein, and activity were quantified by real-time quantitative polymerase chain reaction, quantitative proteomics, and formation of dextrorphan from dextromethorphan, respectively. In the absence of supplemental dexamethasone, CYP2D6 activity, mRNA, and protein were significantly and robustly (>10-fold) induced by all four corticosteroids. However, this CYP2D6 induction was abolished in cells preincubated with supplemental dexamethasone. These data show, for the first time, that CYP2D6 is inducible in vitro but the routine presence of 100 nM dexamethasone in the culture medium masks this induction. Our cortisol data are in agreement with the clinical observation that CYP2D6 is inducible during the third trimester of pregnancy when the plasma concentrations of cortisol increase to ∼1μM. These findings, if confirmed in vivo, have implications for predicting CYP2D6-mediated drug-drug interactions and call for re-evaluation of regulatory guidelines on screening for CYP2D6 induction by xenobiotics. Our findings also suggest that cortisol may be a causative factor in the in vivo induction of CYP2D6 during pregnancy.

  15. Liver kidney microsomal type 1 antibodies reduce the CYP2D6 activity in patients with chronic hepatitis C virus infection.

    PubMed

    Girardin, F; Daali, Y; Gex-Fabry, M; Rebsamen, M; Roux-Lombard, P; Cerny, A; Bihl, F; Binek, J; Moradpour, D; Negro, F; Desmeules, J

    2012-08-01

    Liver kidney microsomal type 1 (LKM-1) antibodies have been shown to decrease the CYP2D6 activity in vitro and are present in a minority of patients with chronic hepatitis C infection. We investigated whether LKM-1 antibodies might reduce the CYP2D6 activity in vivo. All patients enrolled in the Swiss Hepatitis C Cohort Study and tested for LKM-1 antibodies were assessed (n = 1723): 10 eligible patients were matched with patients without LKM-1 antibodies. Patients were genotyped for CYP2D6 variants to exclude individuals with a poor metabolizer genotype. CYP2D6 activity was measured by a specific substrate using the dextromethorphan/dextrorphan metabolic ratio to classify patients into four activity phenotypes. All patients had a CYP2D6 extensive metabolizer genotype. The observed phenotype was concordant with the CYP2D6 genotype in most LKM-negative patients, whereas only three LKM-1 positive patients had a concordant phenotype (six presented an intermediate and one a poor metabolizer phenotype). The median DEM/DOR ratio was sixfold higher in LKM-1 positive than in LKM-1 negative patients (0.096 vs. 0.016, P = 0.004), indicating that CYP2D6 metabolic function was significantly reduced in the presence of LKM-1 antibodies. In chronic hepatitis C patients with LKM-1 antibodies, the CYP2D6 metabolic activity was on average reduced by 80%. The impact of LKM-1 antibodies on CYP2D6-mediated drug metabolism pathways warrants further translational studies. © 2012 Blackwell Publishing Ltd.

  16. Trial of Naltrexone and Dextromethorphan for Gulf War Veterens’ Illness

    DTIC Science & Technology

    2016-03-01

    end of each course of therapy by a routine clinical laboratory, to screen for untoward hematological , metabolic, renal, or hepatic adverse reactions...parameters was to screen for hematologic , hepatic, or renal toxicity. No toxicity was detected in any of these assays in any subject. 8 The Lincoplex

  17. Novel Anticonvulsant Analogs of Dextromethorphan: Improved Efficacy, Potency, Duration and Side-Effect Profile

    DTIC Science & Technology

    1994-02-01

    which is a more potent anticonvul- cough suppressants, exhibits a broad-spectrum anticonvulsant sant (Tortella et al., 1988a; Wong et al, 1988; Aram et... cough sup- A- ANI-037 pressant like DM, we studied the anticonvulsant efficacy and 20 acute behavioral toxicity of DM and a series of novel DM analogs in...AND BRAITMAN, D. J.: Effects of non-opioid antitussives on epileptiform activity and NMDA responses in hippocampal and olfactory cortex mechanism of

  18. [Dextromethorphan (DXM): new methods of intoxications among teenagers--a case description].

    PubMed

    Tomczak, Ewa; Wiergowski, Marek; Jankowski, Zbigniew; Wilmanowska, Jolanta Anita

    2012-01-01

    The study highlighted the problem of intoxication using substances and/or preparations, to which nowadays young people have unrestricted access. Based on the case developed in the Department of Forensic Medicine of the Medical University of Gdansk, our team members were able to gather information showing "ingenuity" of today's teenagers, which was reflected in the types of preparations used to induce a state of euphoria and intoxication. The study was based on the case of a 17-year-old woman, who took Acodin in combination with compressed air used to clean computer keyboards in order to induce psychoactive effects. The study used qualitative and quantitative methods: GC-FID and GC-MS. The results were compared with data from the literature.

  19. Guanfu base A, an antiarrhythmic alkaloid of Aconitum coreanum, Is a CYP2D6 inhibitor of human, monkey, and dog isoforms.

    PubMed

    Sun, Jianguo; Peng, Ying; Wu, Hui; Zhang, Xueyuan; Zhong, Yunxi; Xiao, Yanan; Zhang, Fengyi; Qi, Huanhuan; Shang, Lili; Zhu, Jianping; Sun, Yue; Liu, Ke; Liu, Jinghan; A, Jiye; Ho, Rodney J Y; Wang, Guangji

    2015-05-01

    Guanfu base A (GFA) is a novel heterocyclic antiarrhythmic drug isolated from Aconitum coreanum (Lèvl.) rapaics and is currently in a phase IV clinical trial in China. However, no study has investigated the influence of GFA on cytochrome P450 (P450) drug metabolism. We characterized the potency and specificity of GFA CYP2D inhibition based on dextromethorphan O-demethylation, a CYP2D6 probe substrate of activity in human, mouse, rat, dog, and monkey liver microsomes. In addition, (+)-bufuralol 1'-hydroxylation was used as a CYP2D6 probe for the recombinant form (rCYP2D6), 2D1 (rCYP2D1), and 2D2 (rCYP2D2) activities. Results show that GFA is a potent noncompetitive inhibitor of CYP2D6, with inhibition constant Ki = 1.20 ± 0.33 μM in human liver microsomes (HLMs) and Ki = 0.37 ± 0.16 μM for the human recombinant form (rCYP2D6). GFA is also a potent competitive inhibitor of CYP2D in monkey (Ki = 0.38 ± 0.12 μM) and dog (Ki = 2.4 ± 1.3 μM) microsomes. However, GFA has no inhibitory activity on mouse or rat CYP2Ds. GFA did not exhibit any inhibition activity on human recombinant CYP1A2, 2A6, 2C8, 2C19, 3A4, or 3A5, but showed slight inhibition of 2B6 and 2E1. Preincubation of HLMs and rCYP2D6 resulted in the inactivation of the enzyme, which was attenuated by GFA or quinidine. Beagle dogs treated intravenously with dextromethorphan (2 mg/ml) after pretreatment with GFA injection showed reduced CYP2D metabolic activity, with the Cmax of dextrorphan being one-third that of the saline-treated group and area under the plasma concentration-time curve half that of the saline-treated group. This study suggests that GFA is a specific CYP2D6 inhibitor that might play a role in CYP2D6 medicated drug-drug interaction. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  20. Suppressive effect of the ethanolic extract of adlay bran on cytochrome P-450 enzymes in rat liver and lungs.

    PubMed

    Yao, Hsien-Tsung; Lin, Jia-Hsuan; Chiang, Meng-Tsan; Chiang, Wenchang; Luo, Mei-Nin; Lii, Chong-Kuei

    2011-04-27

    Adlay ( Coix lachryma-jobi L. var. ma-yuen Stapf) is a grass crop and is reported to protect against various diseases such as cancer. To investigate the effect of the ethanolic extract of adlay bran (ABE) on drug-metabolizing enzymes and glutathione-related antioxidant enzymes in rats, three groups of eight male Sprague-Dawley rats each were fed a control diet or a diet containing 5 or 10% ABE for 4 weeks. Significant decreases in microsomal cytochrome P-450 (CYP) 1A1-catalyzed ethoxyresorufin O-deethylation, CYP2C-catalyzed diclofenac 4-hydroxylation, CYP2D-catalyzed dextromethorphan O-demethylation, and CYP3A-catalyzed testosterone 6β-hydroxylation in the liver and CYP1A1-catalyzed ethoxyresorufin O-deethylation in the lungs of rats fed ABE were observed. Immunoblot analyses also showed decreases of CYP1A1, 1A2, 2C6, 2C11, 2D1, 2E1, 3A1, and 3A2 in the liver and CYP1A1 in the lungs. Furthermore, rats fed the 10% ABE diet had a higher glutathione content and glutathione peroxidase, glutathione reductase, and glutathione S-transferase activities in the lungs, but such an increase was not noted in the liver. Inhibition of various CYP-catalyzed enzyme reactions by ABE in rat and human liver microsomes had also been shown. The results of this study indicate that ABE feeding may suppress CYP enzyme activities and CYP protein expression in the liver and lungs of rats. Moreover, the increase of the antioxidant potential by ABE is tissue-specific.

  1. In vitro Inhibitory Effect of Gymnema sylvestre Extracts and Total Gymnemic Acids Fraction on Select Cytochrome P450 Activities in Rat Liver Microsomes.

    PubMed

    Vaghela, Madhuri; Iyer, Krishna; Pandita, Nancy

    2017-10-10

    Gymnema sylvestre R. Br. is a well-known Indian medicinal herb. Gymnemic acids are pentacyclic triterpenes saponins and active phytoconstituents of Gymnema sylvestre. The study aimed at evaluation of the in vitro rat liver cytochrome P450 (CYP) inhibition potential of extracts and total gymnemic acid (TA)-enriched fractions from G. sylvestre. Standardization of G. sylvestre [ethanolic (EL), hydroethanolic (HE), total acid of ethanolic (TAE), total acid of hydroethanolic (TAHE) and total acid of aqueous (TAAQ) extract] was done with respect to deacyl gymnemic acid (DAGA), using reverse phase-high performance liquid chromatography (RP-HPLC). Total triterpenoid content was determined by vanillin perchloric acid assay. Total triterpene content was found to be the highest in TAAQ (59.86 ± 0.005% w/w) and TAE (49.77 ± 0.009% w/w). TAAQ showed IC50 ≤ 50 µg/ml for all selected CYP activities. Testosterone 6β-hydroxylation was strongly inhibited by TAE (IC50: 15.48 ± 2.13 µg/ml) and was moderately by TAAQ and EL with IC50 ≥ 50 µg/ml. Flurbiprofen 4'-hydroxylation was subject to strong, weak and moderate inhibition by TAAQ (IC50: 34.67 ± 1.38 µg/ml), TAE (IC50: ≥ 50 µg/ml) and EL (IC50: > 50 µg/ml), respectively. Dextromethorphan O-demethylation was inhibited by TAHE and TAAQ. In vitro inhibition studies suggested that TA strongly inhibits activity of selected CYP. This inhibition may possibly be due to triterpenoids and gymnemic acids that have been reported to be present in it. Data also suggest a potential for possible in vivo herb-drug interactions involving G. sylvestre and other medications that are metabolized by the same CYP.

  2. Effects of green tea catechins on cytochrome P450 2B6, 2C8, 2C19, 2D6 and 3A activities in human liver and intestinal microsomes.

    PubMed

    Misaka, Shingen; Kawabe, Keisuke; Onoue, Satomi; Werba, José Pablo; Giroli, Monica; Tamaki, Sekihiro; Kan, Toshiyuki; Kimura, Junko; Watanabe, Hiroshi; Yamada, Shizuo

    2013-01-01

    The effects of green tea catechins on the main drug-metabolizing enzymatic system, cytochrome P450 (CYP), have not been fully elucidated. The objective of the present study was to evaluate the effects of green tea extract (GTE, total catechins 86.5%, w/w) and (-)-epigallocatechin-3-gallate (EGCG) on the activities of CYP2B6, CYP2C8, CYP2C19, CYP2D6 and CYP3A in vitro, using pooled human liver and intestinal microsomes. Bupropion hydroxylation, amodiaquine N-deethylation, (S)-mephenytoin 4'-hydroxylation, dextromethorphan O-demethylation and midazolam 1'-hydroxylation were assessed in the presence or absence of various concentrations of GTE and EGCG to test their effects on CYP2B6, CYP2C8, CYP2C19, CYP2D6 and CYP3A activities, respectively. Each metabolite was quantified using UPLC/ESI-MS, and the inhibition kinetics of GTE and EGCG on CYP enzymes was analyzed. In human liver microsomes, IC50 values of GTE were 5.9, 4.5, 48.7, 25.1 and 13.8 µg/mL, for CYP2B6, CYP2C8, CYP2C19, CYP2D6 and CYP3A, respectively. ECGC also inhibited these CYP isoforms with properties similar to those of GTE, and produced competitive inhibitions against CYP2B6 and CYP2C8, and noncompetitive inhibition against CYP3A. In human intestinal microsomes, IC50 values of GTE and EGCG for CYP3A were 18.4 µg/mL and 31.1 µM, respectively. EGCG moderately inhibited CYP3A activity in a noncompetitive manner. These results suggest that green tea catechins cause clinically relevant interactions with substrates for CYP2B6 and CYP2C8 in addition to CYP3A.

  3. Effect of antipsychotic drugs on human liver cytochrome P-450 (CYP) isoforms in vitro: preferential inhibition of CYP2D6.

    PubMed

    Shin, J G; Soukhova, N; Flockhart, D A

    1999-09-01

    The ability of antipsychotic drugs to inhibit the catalytic activity of five cytochrome P-450 (CYP) isoforms was compared using in vitro human liver microsomal preparations to evaluate the relative potential of these drugs to inhibit drug metabolism. The apparent kinetic parameters for enzyme inhibition were determined by nonlinear regression analysis of the data. All antipsychotic drugs tested competitively inhibited dextromethorphan O-demethylation, a selective marker for CYP2D6, in a concentration-dependent manner. Thioridazine and perphenazine were the most potent, with IC(50) values (2.7 and 1.5 microM) that were comparable to that of quinidine (0.52 microM). The estimated K(i) values for CYP2D6-catalyzing dextrorphan formation were ranked in the following order: perphenazine (0.8 microM), thioridazine (1.4 microM), chlorpromazine (6.4 microM), haloperidol (7.2 microM), fluphenazine (9.4 microM), risperidone (21.9 microM), clozapine (39.0 microM), and cis-thiothixene (65.0 microM). No remarkable inhibition of other CYP isoforms was observed except for moderate inhibition of CYP1A2-catalyzed phenacetin O-deethylation by fluphenazine (K(i) = 40.2 microM) and perphenazine (K(i) = 65.1). The estimated K(i) values for the inhibition of CYP2C9, 2C19, and 3A were >300 microM in almost all antipsychotics tested. These results suggest that antipsychotic drugs exhibit a striking selectivity for CYP2D6 compared with other CYP isoforms. This may reflect a remarkable commonality of structure between the therapeutic targets for these drugs, the transporters, and metabolic enzymes that distribute and eliminate them. Clinically, coadministration of these medicines with drugs that are primarily metabolized by CYP2D6 may result in significant drug interactions.

  4. Comparative metabolic capabilities and inhibitory profiles of CYP2D6.1, CYP2D6.10, and CYP2D6.17.

    PubMed

    Shen, Hongwu; He, Minxia M; Liu, Houfu; Wrighton, Steven A; Wang, Li; Guo, Bin; Li, Chuan

    2007-08-01

    Polymorphisms in the cytochrome P450 2D6 (CYP2D6) gene are a major cause of pharmacokinetic variability in human. Although the poor metabolizer phenotype is known to be caused by two null alleles leading to absence of functional CYP2D6 protein, the large variability among individuals with functional alleles remains mostly unexplained. Thus, the goal of this study was to examine the intrinsic enzymatic differences that exist among the several active CYP2D6 allelic variants. The relative catalytic activities (enzyme kinetics) of three functionally active human CYP2D6 allelic variants, CYP2D6.1, CYP2D6.10, and CYP2D6.17, were systematically investigated for their ability to metabolize a structurally diverse set of clinically important CYP2D6-metabolized drugs [atomoxetine, bufuralol, codeine, debrisoquine, dextromethorphan, (S)-fluoxetine, nortriptyline, and tramadol] and the effects of various CYP2D6-inhibitors [cocaine, (S)-fluoxetine, (S)-norfluoxetine, imipramine, quinidine, and thioridazine] on these three variants. The most significant difference observed was a consistent but substrate-dependent decease in the catalytic efficiencies of cDNA-expressed CYP2D6.10 and CYP2D6.17 compared with CYP2D6.1, yielding 1.32 to 27.9 and 7.33 to 80.4% of the efficiency of CYP2D6.1, respectively. The most important finding from this study is that there are mixed effects on the functionally reduced allelic variants in enzyme-substrate affinity or enzyme-inhibitor affinity, which is lower, higher, or comparable to that for CYP2D6.1. Considering the rather high frequencies of CYP2D6*10 and CYP2D6*17 alleles for Asians and African Americans, respectively, these data provide further insight into ethnic differences in CYP2D6-mediated drug metabolism. However, as with all in vitro to in vivo extrapolations, caution should be applied to the clinical consequences.

  5. Endoxifen levels and its association with CYP2D6 genotype and phenotype: evaluation of a southern Brazilian population under tamoxifen pharmacotherapy.

    PubMed

    Antunes, Marina V; Linden, Rafael; Santos, Tamyris V; Wallemacq, Pierre; Haufroid, Vincent; Classen, Jean-François; Andreolla, Huander; Costa, Nathalia; Fontanive, Tiago O; Rosa, Daniela D

    2012-08-01

    An association between CYP2D6 variation and clinical outcomes among women with breast cancer treated with tamoxifen (TAM) has been demonstrated, such that the presence of 2 functional CYP2D6 alleles was associated with better clinical outcomes. This association is mainly due to the CYP2D6-mediated hydroxylation of N-desmethyltamoxifen (NDT) to yield endoxifen (EDF), which because of its high antiestrogenic potency, is mainly responsible for the therapeutic efficacy of TAM. The aim of this study was to evaluate the relation of CYP2D6 genotyping and phenotyping with EDF levels and [NDT]/[EDF] metabolic ratio in breast cancer patients from South of Brazil under TAM therapy. Trough blood samples were collected from 97 patients. CYP2D6 genotyping was performed with a luminex assay and calculation of genotypic activity scores. Tamoxifen and metabolites EDF, NDT, and 4-hydroxy-TAM were measured in plasma by high performance liquid chromatography with photo diode array detector. CYP2D6 phenotyping was performed by the determination of dextromethorphan (DMT) and dextrorphan (DTF) by high-performance liquid chromatography with fluorescence detection at plasma collected 3 hours after oral administration of 33 mg of DMF. Phenotypes were given according to [DMT]/[DTF] metabolic ratio. CYP2D6 genotyping indicated a prevalence of 4.1% poor metabolizer, 4.1% intermediate metabolizer, 49.5% extensive metabolizer slow activity, 39.2% extensive metabolizer fast activity, and 3.1% ultrarapid metabolizer. Genotype (genotypic activity scores) was significantly correlated with phenotype ([DMT]/[DTF]), with a moderate association (rs = -0.463; P < 0.001). Median plasma concentrations (nanograms per milliliter; N = 97) were TAM 57.17; 4-hydroxy-TAM 1.01; EDF 6.21; NDT 125.50. EDF levels were lower in poor metabolizers than that in extensive metabolizers (P < 0.05). Phenotype showed stronger, but still moderate, association with EDF and [NDT]/[EDF] than genotype (r = -0.507, r = 0.625, P

  6. Abuse of Dextromethorphan-Based Cough Syrup as a Substitute for Licit and Illicit Drugs: A Theoretical Framework.

    ERIC Educational Resources Information Center

    Darboe, Momodou N.

    1996-01-01

    Discusses the emergence of new types of abused drugs in the United States. Notes that young persons often search for substitutes for better-known substances. It is unclear, however, what factors determine the choice of drug or substance for experimentation, considering the wide range of choices. This paper attempts to delineate the factors that…

  7. Hallucinogens and Dissociative Drugs, Including LSD, PCP, Ketamine, Dextromethorphan. National Institute on Drug Abuse Research Report Series.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHHS/PHS), Rockville, MD.

    Research is developing a clearer picture of the dangers of mind-altering drugs. The goal of this report is to present the latest information to providers to help them strengthen their prevention and treatment efforts. A description is presented of dissociative drugs, and consideration is given as to why people take hallucinogens. The physical…

  8. Abuse of Dextromethorphan-Based Cough Syrup as a Substitute for Licit and Illicit Drugs: A Theoretical Framework.

    ERIC Educational Resources Information Center

    Darboe, Momodou N.

    1996-01-01

    Discusses the emergence of new types of abused drugs in the United States. Notes that young persons often search for substitutes for better-known substances. It is unclear, however, what factors determine the choice of drug or substance for experimentation, considering the wide range of choices. This paper attempts to delineate the factors that…

  9. Metabolic capabilities of cytochrome P450 enzymes in Chinese liver microsomes compared with those in Caucasian liver microsomes

    PubMed Central

    Yang, Junling; He, Minxia M; Niu, Wei; Wrighton, Steven A; Li, Li; Liu, Yang; Li, Chuan

    2012-01-01

    AIM The most common causes of variability in drug response include differences in drug metabolism, especially when the hepatic cytochrome P450 (CYP) enzymes are involved. The current study was conducted to assess the differences in CYP activities in human liver microsomes (HLM) of Chinese or Caucasian origin. METHODS The metabolic capabilities of CYP enzymes in 30 Chinese liver microsomal samples were compared with those of 30 Caucasian samples utilizing enzyme kinetics. Phenacetin O-deethylation, coumarin 7-hydroxylation, bupropion hydroxylation, amodiaquine N-desethylation, diclofenac 4′-hydroxylation (S)-mephenytoin 4′-hydroxylation, dextromethorphan O-demethylation, chlorzoxazone 6-hydroxylation and midazolam 1′-hydroxylation/testosterone 6β-hydroxylation were used as probes for activities of CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A, respectively. Mann-Whitney U test was used to assess the differences. RESULTS The samples of the two ethnic groups were not significantly different in cytochrome-b5 concentrations but were significantly different in total CYP concentrations and NADPH-P450 reductase activity (P < 0.05). Significant ethnic differences in intrinsic clearance were observed for CYP1A2, CYP2C9, CYP2C19 and CYP2E1; the median values of the Chinese group were 54, 58, 26, and 35% of the corresponding values of the Caucasian group, respectively. These differences were associated with differences in Michaelis constant or maximum velocity. Despite negligible difference in intrinsic clearance, the Michaelis constant of CYP2B6 appeared to have a significant ethnic difference. No ethnic difference was observed for CYP2A6, CYP2C8, CYP2D6 and CYP3A. CONCLUSIONS These data extend our knowledge on the ethnic differences in CYP enzymes and will have implications for drug discovery and drug therapy for patients from different ethnic origins. PMID:21815912

  10. Identification of metabolic pathways involved in the biotransformation of tolperisone by human microsomal enzymes.

    PubMed

    Dalmadi, Balázs; Leibinger, János; Szeberényi, Szabolcs; Borbás, Tímea; Farkas, Sándor; Szombathelyi, Zsolt; Tihanyi, Károly

    2003-05-01

    The in vitro metabolism of tolperisone, 1-(4-methyl-phenyl)-2-methyl-3-(1-piperidino)-1-propanone-hydrochloride, a centrally acting muscle relaxant, was examined in human liver microsomes (HLM) and recombinant enzymes. Liquid chromatography-mass spectrometry measurements revealed methyl-hydroxylation (metabolite at m/z 261; M1) as the main metabolic route in HLM, however, metabolites of two mass units greater than the parent compound and the hydroxy-metabolite were also detected (m/z 247 and m/z 263, respectively). The latter was identified as carbonyl-reduced M1, the former was assumed to be the carbonyl-reduced parent compound. Isoform-specific cytochrome P450 (P450) inhibitors, inhibitory antibodies, and experiments with recombinant P450s pointed to CYP2D6 as the prominent enzyme in tolperisone metabolism. CYP2C19, CYP2B6, and CYP1A2 are also involved to a smaller extent. Hydroxymethyl-tolperisone formation was mediated by CYP2D6, CYP2C19, CYP1A2, but not by CYP2B6. Tolperisone competitively inhibited dextromethorphan O-demethylation and bufuralol hydroxylation (K(i) = 17 and 30 microM, respectively). Tolperisone inhibited methyl p-tolyl sulfide oxidation (K(i) = 1200 microM) in recombinant flavin-containing monooxygenase 3 (FMO3) and resulted in a 3-fold (p < 0.01) higher turnover number using rFMO3 than that of control microsomes. Experiments using nonspecific P450 inhibitors-SKF-525A, 1-aminobenzotriazole, 1-benzylimidazole, and anti-NADPH-P450-reductase antibodies-resulted in 61, 47, 49, and 43% inhibition of intrinsic clearance in HLM, respectively, whereas hydroxymethyl-metabolite formation was inhibited completely by nonspecific chemical inhibitors and by 80% with antibodies. Therefore, it was concluded that tolperisone undergoes P450-dependent and P450-independent microsomal biotransformations to the same extent. On the basis of metabolites formed and indirect evidences of inhibition studies, a considerable involvement of a microsomal reductase is

  11. Methoxyl groups of lignin are essential carbon donors in C1 metabolism of Sphingobium sp. SYK-6.

    PubMed

    Sonoki, Tomonori; Masai, Eiji; Sato, Kanna; Kajita, Shinya; Katayama, Yoshihiro

    2009-09-01

    Sphingobium sp. SYK-6 can utilize lignin biphenyl compounds, such as 2,2'-dihydroxy-3,3'-dimethoxy-5,5'-dicarboxybiphenyl (DDVA). In the metabolism of DDVA, this microorganism exploits two O -demethylation systems with different substrate specificities, namely, a DDVA-specific oxygenative O -demethylation system and a vanillate-specific (VA-specific) tetrahydrofolate-dependent (THF-dependent) methyltransferase system. We examined the way in which these two systems interact in the metabolism of lignin in Sphingobium sp. SYK-6. Our results indicate that THF accepts methyl groups derived not only from the THF-dependent O -demethylation of VA but also from the oxygenative O -demethylation of DDVA. Thus, the methoxyl groups of lignin model compounds are an essential source of carbon in Sphingobium sp. SYK-6. ((c) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).

  12. Monitoring and Counteracting Functional Deterioration in Parkinson’s Disease: A Multilevel Integrative Approach in a Primate Model System

    DTIC Science & Technology

    2006-09-01

    antagonist riluzole and the anti-oxidant dextromethorphan were selected. However, dextromethorphan shows besides its anti-oxidative action also activity...against excitotoxicity. This would interfere with the outcome of the study. Therefore, we replaced dextromethorphan by EGCG with a strong anti

  13. Neuroprotective Treatment of Laser-Induced Retinal Injuries

    DTIC Science & Technology

    2001-10-01

    to evaluate the neuroprotective effect of dextromethorphan , memantine and brimonidine in our rat model of laser- induced retinal-lesions Methods: Argon... dextromethorphan , memantine or brimonidine. The control groups (18 rats for each compound) received the solvent at the same volume and schedule as...size and the magnitude of photoreceptor nuclei loss within the lesions. Conclusions: Systemic treatments with dextromethorphan , memantine or brimonidine

  14. Dual Therapeutic Effects of C-10068, a Dextromethorphan Derivative, Against Post-Traumatic Nonconvulsive Seizures and Neuroinflammation in a Rat Model of Penetrating Ballistic-Like Brain Injury.

    PubMed

    Lu, Xi-Chun May; Shear, Deborah A; Graham, Philip B; Bridson, Gary W; Uttamsingh, Vinita; Chen, Zhiyong; Leung, Lai Yee; Tortella, Frank C

    2015-10-15

    Post-traumatic seizures can exacerbate injurious outcomes of severe brain trauma, yet effective treatments are limited owing to the complexity of the pathology underlying the concomitant occurrence of both events. In this study, we tested C-10068, a novel deuterium-containing analog of (+)-N-methyl-3-ethoxymorphinan, in a rat model of penetrating ballistic-like brain injury (PBBI) and evaluated the effects of C-10068 on PBBI-induced nonconvulsive seizures (NCS), acute neuroinflammation, and neurofunctional outcomes. NCS were detected by electroencephalographic monitoring. Neuroinflammation was evaluated by immunohistochemical markers, for example, glial fibrillary acidic protein and major histocompatibility complex class I, for activation of astrocytes and microglia, respectively. Neurofunction was tested using rotarod and Morris water maze tasks. Three infusion doses of C-10068 (1.0, 2.5, and 5.0 mg/kg/h × 72 h) were tested in the antiseizure study. Neuroinflammation and neurofunction were evaluated in animals treated with 5.0 mg/kg/h × 72 h C-10068. Compared to vehicle treatment, C-10068 dose dependently reduced PBBI-induced NCS incidence (40-50%), frequency (20-70%), and duration (30-82%). The most effective antiseizure dose of C-10068 (5.0 mg/kg/h × 72 h) also significantly attenuated hippocampal astrocyte activation and perilesional microglial reactivity post-PBBI. Within C-10068-treated animals, a positive correlation was observed in reduction in NCS frequency and reduction in hippocampal astrocyte activation. Further, C-10068 treatment significantly attenuated astrocyte activation in seizure-free animals. However, C-10068 failed to improve PBBI-induced motor and cognitive functions with the dosing regimen used in this study. Overall, the results indicating that C-10068 exerts both potent antiseizure and antiinflammatory effects are promising and warrant further investigation.

  15. A Comparison of the Effects of Preemptive Oral Dextromethorphan on Perceived Postoperative Pain in Male and Female Patients Undergoing Arthroscopic Knee surgery

    DTIC Science & Technology

    2003-12-01

    subjects were randomly assigned to either a treatment group receiving . lmg/kg ketimine or a control group receiving a placebo of .9% saline. The study... Postoperative pain leads to increased morbidity, length of stay, and health care costs. Several studies have shown that preemptively administered N...methyl-D-aspartate (NMDA) antagonists, such as ketimine, are effective in decreasing perception of postoperative pain. To date, there have not been any

  16. Dual Therapeutic Effects of C-10068, a Dextromethorphan Derivative, Against Post-Traumatic Nonconvulsive Seizures and Neuroinflammation in a Rat Model of Penetrating Ballistic-Like Brain Injury

    PubMed Central

    Shear, Deborah A.; Graham, Philip B.; Bridson, Gary W.; Uttamsingh, Vinita; Chen, Zhiyong; Leung, Lai Yee; Tortella, Frank C.

    2015-01-01

    Abstract Post-traumatic seizures can exacerbate injurious outcomes of severe brain trauma, yet effective treatments are limited owing to the complexity of the pathology underlying the concomitant occurrence of both events. In this study, we tested C‐10068, a novel deuterium-containing analog of (+)-N-methyl-3-ethoxymorphinan, in a rat model of penetrating ballistic-like brain injury (PBBI) and evaluated the effects of C-10068 on PBBI-induced nonconvulsive seizures (NCS), acute neuroinflammation, and neurofunctional outcomes. NCS were detected by electroencephalographic monitoring. Neuroinflammation was evaluated by immunohistochemical markers, for example, glial fibrillary acidic protein and major histocompatibility complex class I, for activation of astrocytes and microglia, respectively. Neurofunction was tested using rotarod and Morris water maze tasks. Three infusion doses of C-10068 (1.0, 2.5, and 5.0 mg/kg/h×72 h) were tested in the antiseizure study. Neuroinflammation and neurofunction were evaluated in animals treated with 5.0 mg/kg/h×72 h C-10068. Compared to vehicle treatment, C-10068 dose dependently reduced PBBI-induced NCS incidence (40–50%), frequency (20–70%), and duration (30–82%). The most effective antiseizure dose of C-10068 (5.0 mg/kg/h×72 h) also significantly attenuated hippocampal astrocyte activation and perilesional microglial reactivity post-PBBI. Within C-10068-treated animals, a positive correlation was observed in reduction in NCS frequency and reduction in hippocampal astrocyte activation. Further, C-10068 treatment significantly attenuated astrocyte activation in seizure-free animals. However, C-10068 failed to improve PBBI-induced motor and cognitive functions with the dosing regimen used in this study. Overall, the results indicating that C-10068 exerts both potent antiseizure and antiinflammatory effects are promising and warrant further investigation. PMID:25794265

  17. Biosynthesis of glycosylated derivatives of tylosin in Streptomyces venezuelae.

    PubMed

    Han, Ah Reum; Park, Sung Ryeol; Park, Je Won; Lee, Eun Yeol; Kim, Dong-Myung; Kim, Byung-Gee; Yoon, Yeo Joon

    2011-06-01

    Streptomyces venezuelae YJ028, bearing a deletion of the entire biosynthetic gene cluster encoding the pikromycin polyketide synthases and desosamine biosynthetic enzymes, was used as a bioconversion system for combinatorial biosynthesis of glycosylated derivatives of tylosin. Two engineered deoxysugar biosynthetic pathways for the biosynthesis of TDP-3-O-demethyl-D-chalcose or TDP-Lrhamnose in conjunction with the glycosyltransferaseauxiliary protein pair DesVII/DesVIII were expressed in a S. venezuelae YJ028 mutant strain. Supplementation of each mutant strain capable of producing TDP-3-O-demethyl- D-chalcose or TDP-L-rhamnose with tylosin aglycone tylactone resulted in the production of the 3-O-demethyl- D-chalcose, D-quinovose, or L-rhamnose-glycosylated tylactone.

  18. Brompheniramine

    MedlinePlus

    Children's Dimetapp® Cold and Cough (as a combination product containing Brompheniramine, Dextromethorphan, Phenylephrine) ... Trexbrom® (as a combination product containing Brompheniramine, Chlophedianol, Phenylephrine)

  19. Metabolism of melatonin by cytochrome P-450s in rat liver mitochondria and microsomes

    PubMed Central

    Semak, Igor; Korik, Elena; Antonova, Maria; Wortsman, Jacobo; Slominski, Andrzej

    2008-01-01

    In the present study we provide direct evidence for the involvement of rat microsomal cytochrome P450s in melatonin O-demethylation and hydroxylation at two different positions: 2 and 6, as well as generation of N1-acetyl-N2-formyl-5-methoxy-kynuramine (AFMK) and two unknown products. Moreover, we found that mitochondrial cytochrome P450s also converts melatonin into AFMK, N-acetylserotonin (NAS), 2-hydroxymelatonin, 6-hydroxymelatonin and the same two unknown products. Eadie-Hofstee plots for 6-hydroxylation and O-demethylation reactions were curvilinear for all tested fractions, suggestive of involvement of at least two components, one with a high affinity and low capacity, and another with a low affinity and high capacity. Mitochondrial cytochrome P450s exhibited higher affinity (suggesting lower Km value) and higher Vmax for melatonin 6-hydroxylation and O-demethylation for both high-affinity and low-affinity components as compared to microsomal enzymes. The intrinsic clearance for melatonin hydroxylation by high- and low-affinity components displayed the highest values in all tested fractions, indicating that both mitochondrial and microsomal cytochrome P-450s metabolize melatonin principally by 6-hydroxylation, with O-demethylation representing a minor metabolic pathway. PMID:18717775

  20. Metabolism of melatonin by cytochrome P450s in rat liver mitochondria and microsomes.

    PubMed

    Semak, Igor; Korik, Elena; Antonova, Maria; Wortsman, Jacobo; Slominski, Andrzej

    2008-11-01

    In the present study we provide direct evidence for the involvement of rat microsomal cytochrome P450s in melatonin O-demethylation and hydroxylation at two different positions: 2 and 6, as well as generation of N(1)-acetyl-N(2)-formyl-5-methoxy-kynuramine (AFMK) and two unknown products. Moreover, we found that mitochondrial cytochrome P450s also converts melatonin into AFMK, N-acetylserotonin, 2-hydroxymelatonin, 6-hydroxymelatonin and the same two unknown products. Eadie-Hofstee plots for 6-hydroxylation and O-demethylation reactions were curvilinear for all tested fractions, suggestive of involvement of at least two components, one with a high affinity and low capacity, and another with a low affinity and high capacity. Mitochondrial cytochrome P450s exhibited higher affinity (suggesting lower K(m) value) and higher V(max) for melatonin 6-hydroxylation and O-demethylation for both high-affinity and low-affinity components as compared with microsomal enzymes. The intrinsic clearance for melatonin hydroxylation by high- and low-affinity components displayed the highest values in all tested fractions, indicating that both mitochondrial and microsomal cytochrome P450s metabolize melatonin principally by 6-hydroxylation, with O-demethylation representing a minor metabolic pathway.

  1. Comparative Computational Study on the Reaction of Chloroacetone with Trimethylphosphite: Perkow versus Michaelis-Arbuzov Reaction Paths.

    PubMed

    Espinosa Ferao, Arturo

    2017-08-31

    Two competitive mechanistic pathways for the reaction between trimethyl phosphite and chloroacetone are analyzed by high-level calculations. FMO analysis and HSAB-derived descriptors point to a preferential initial interaction of the nucleophile with the carbonyl group as electrophile. The Perkow reaction starts by chelotropic addition of the P atom to the carbonyl C-O bond, which is the rate-determining step in THF or CH2Cl2 solution, yielding an oxaphosphirane intermediate. The oxaphosphirane undergoes sequential P-C bond cleavage with elimination of chloride ion and O-demethylation. The alternative Michaelis-Arbuzov reaction involves nucleophilic displacement of chloride by the P atom and subsequent O-demethylation. The Perkow path is kinetically and thermodynamically favored with respect to the Michaelis-Arbuzov path in the gas phase, but it is only kinetically preferred in polar (THF or CH2Cl2) solvents.

  2. Codeine analgesia is due to codeine-6-glucuronide, not morphine.

    PubMed

    Vree, T B; van Dongen, R T; Koopman-Kimenai, P M

    2000-01-01

    Eighty per cent of codeine is conjugated with glucuronic acid to codeine-6-glucuronide. Only 5% of the dose is O-demethylated to morphine, which in turn is immediately glucuronidated at the 3- and 6-position and excreted renally. Based on the structural requirement of the opiate molecule for interaction with the mu-receptor to result in analgesia, codeine-6-glucuronide in analogy to morphine-6-glucuronide must be the active constituent of codeine. Poor metabolisers of codeine, those who lack the CYP450 2D6 isoenzyme for the O-demethylation to morphine, experience analgesia from codeine-6-glucuronide. Analgesia of codeine does not depend on the formation of morphine and the metaboliser phenotype.

  3. Hydrocodone

    MedlinePlus

    ... any of the following symptoms: irritability, hyperactivity, abnormal sleep, high-pitched cry, uncontrollable shaking of a part ... Cordarone, Nexterone, Pacerone); azithromycin (Zithromax, Zmax); butorphanol; ... (Celexa); cyclobenzaprine (Amrix); dextromethorphan (found in many cough ...

  4. Codeine

    MedlinePlus

    ... and carisoprodol; and as an ingredient in many cough and cold medications. This monograph only includes information ... the following: cyclobenzaprine (Amrix); dextromethorphan (found in many cough medications; in Nuedexta); lithium (Lithobid); medications for cough, ...

  5. Fentanyl Transdermal Patch

    MedlinePlus

    ... dextromethorphan (found in many cough medications; in Nuedexta); lithium (Lithobid); medications for migraine headaches such as almotriptan ( ... pressure; or thyroid, heart, liver, pancreas, gallbladder, or kidney disease.tell your doctor if you are breastfeeding.you ...

  6. Toxicological Findings of Pilots Involved in Aviation Accidents Operated under 14 CFR Part 135

    DTIC Science & Technology

    2009-08-01

    pilots), dextromethorphan (2 pilots), doxylamine (1 pilot), naphazoline (1 pilot), and theophylline (1 pilot) . Other medications found in these 33...aviation accidents between 1997 and 2007. 6 pseudoephedrine, phenylpropanolamine, dextrometho- rphan, doxylamine , and dextrorphan . Finally, lidocaine

  7. Phenylephrine

    MedlinePlus

    Sine-Off Cough/Cold® (as a combination product containing Acetaminophen, Dextromethorphan, Guaifenesin, Phenylephrine) ... Sine-Off Non-Drowsy® (as a combination product containing Acetaminophen, Phenylephrine)

  8. Identification of metabolites of selected benzophenanthridine alkaloids and their toxicity evaluation.

    PubMed

    Sandor, Roman; Midlik, Adam; Sebrlova, Kristyna; Dovrtelova, Gabriela; Noskova, Kristyna; Jurica, Jan; Slaninova, Iva; Taborska, Eva; Pes, Ondrej

    2016-03-20

    Selected benzo[c]phenathridine alkaloids were biotransformed using rat liver microsomes and identified by liquid chromatography and mass spectrometry. While the metabolites of commercially available sanguinarine and chelerythrine have been studied in detail, data about the metabolism of the minor alkaloids remained unknown. Reactions involved in transformation include single and/or double O-demethylation, demethylenation, reduction, and hydroxylation. Two metabolites, when isolated, purified and tested for toxicity, were found to be less toxic than the original compounds.

  9. 40 CFR 180.449 - Avermectin B1 and its delta-8,9-isomer; tolerances for residues.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Avermectin B1 and its delta-8,9-isomer... Tolerances § 180.449 Avermectin B1 and its delta-8,9-isomer; tolerances for residues. (a) General. Tolerances... (5-O-demethyl-25-de(1-methylpropyl)-25-(1-methylethyl) avermectin A1) and its delta-8,9-isomer in...

  10. 40 CFR 180.449 - Avermectin B1 and its delta-8,9-isomer; tolerances for residues.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Avermectin B1 and its delta-8,9-isomer... Tolerances § 180.449 Avermectin B1 and its delta-8,9-isomer; tolerances for residues. (a) General. Tolerances... (5-O-demethyl-25-de(1-methylpropyl)-25-(1-methylethyl) avermectin A1) and its delta-8,9-isomer in...

  11. Regio- and Stereo-Selective Oxidation of a Cardiovascular Drug, Metoprolol, Mediated by Cytochrome P450 2D and 3A Enzymes in Marmoset Livers.

    PubMed

    Uehara, Shotaro; Ishii, Sakura; Uno, Yasuhiro; Inoue, Takashi; Sasaki, Erika; Yamazaki, Hiroshi

    2017-08-01

    A β-blocker, metoprolol, is one of the in vivo probes for human cytochrome P450 (P450) 2D6. Investigation of nonhuman primate P450 enzymes helps to improve the accuracy of the extrapolation of pharmacokinetic data from animals into humans. Common marmosets (Callithrix jacchus) are a potential primate model for preclinical research, but the detailed roles of marmoset P450 enzymes in metoprolol oxidation remain unknown. In this study, regio- and stereo-selectivity of metoprolol oxidations by a variety of P450 enzymes in marmoset and human livers were investigated in vitro. Although liver microsomes from cynomolgus monkeys and rats preferentially mediated S-metoprolol O-demethylation and R-metoprolol α-hydroxylation, respectively, those from humans, marmosets, minipigs, and dogs preferentially mediated R-metoprolol O-demethylation, in contrast to the slow rates of R- and S-metoprolol oxidation in mouse liver microsomes. R- and S-metoprolol O-demethylation activities in marmoset livers were strongly inhibited by quinidine and ketoconazole, and were significantly correlated with bufuralol 1'-hydroxylation and midazolam 1'-hydroxylation activities and also with P450 2D and 3A4 contents, which is different from the case in human livers that did not have any correlations with P450 3A-mediated midazolam 1'-hydroxylation. Recombinant human P450 2D6 enzyme and marmoset P450 2D6/3A4 enzymes effectively catalyzed R-metoprolol O-demethylation, comparable to the activities of human and marmoset liver microsomes, respectively. These results indicated that the major roles of P450 2D enzymes for the regio- and stereo-selectivity of metoprolol oxidation were similar between human and marmoset livers, but the minor roles of P450 3A enzymes were unique to marmosets. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

  12. Identification of novel and improved antimitotic agents derived from noscapine.

    PubMed

    Anderson, James T; Ting, Anthony E; Boozer, Sherry; Brunden, Kurt R; Crumrine, Chris; Danzig, Joel; Dent, Tom; Faga, Laurel; Harrington, John J; Hodnick, William F; Murphy, Steven M; Pawlowski, Gary; Perry, Robert; Raber, Amy; Rundlett, Stephen E; Stricker-Krongrad, Alain; Wang, Jianmin; Bennani, Youssef L

    2005-11-17

    Analogues of the natural product noscapine were synthesized and their potential as antitumor agents evaluated. The discovery of a novel regioselective O-demethylation facilitated the synthesis of the potent aniline 6, which arrests mammalian cells in the G2/M phase of the cell cycle at 0.1 microM and also affects tubulin polymerization. Aniline 6 is orally bioavailable and is 250-fold more potent than noscapine in reducing cell proliferation in rapidly dividing cells.

  13. Structure of the cobalamin-binding protein of a putative O-demethylase from Desulfitobacterium hafniense DCB-2

    SciTech Connect

    Sjuts, Hanno; Dunstan, Mark S.; Fisher, Karl; Leys, David

    2013-08-01

    The first crystal structure of the vitamin B12-binding protein from a three-component O-demethylase enzyme system is reported. During O-demethylation methyl groups are transferred from phenyl methyl ethers to tetrahydrofolate via methyl-B12 intermediates. This study describes the identification and the structural and spectroscopic analysis of a cobalamin-binding protein (termed CobDH) implicated in O-demethylation by the organohalide-respiring bacterium Desulfitobacterium hafniense DCB-2. The 1.5 Å resolution crystal structure of CobDH is presented in the cobalamin-bound state and reveals that the protein is composed of an N-terminal helix-bundle domain and a C-terminal Rossmann-fold domain, with the cobalamin coordinated in the base-off/His-on conformation similar to other cobalamin-binding domains that catalyse methyl-transfer reactions. EPR spectroscopy of CobDH confirms cobalamin binding and reveals the presence of a cob(III)alamin superoxide, indicating binding of oxygen to the fully oxidized cofactor. These data provide the first structural insights into the methyltransferase reactions that occur during O-demethylation by D. hafniense.

  14. Abuse of nutmeg (Myristica fragrans Houtt.): studies on the metabolism and the toxicologic detection of its ingredients elemicin, myristicin, and safrole in rat and human urine using gas chromatography/mass spectrometry.

    PubMed

    Beyer, Jochen; Ehlers, Dorothea; Maurer, Hans H

    2006-08-01

    Seeds of nutmeg are used as spice, but they are also abused because of psychotropic effects described after ingestion of large doses. It was postulated that these effects could be attributable to metabolic formation of amphetamine derivatives from the main nutmeg ingredients elemicin (EL), myristicin (MY), and safrole (SA). In a case of a suspected nutmeg abuse, neither such amphetamine derivatives nor the main nutmeg ingredients could be detected in urine. The metabolites of EL, MY, and SA were identified using gas chromatography-mass spectrometry in rat urine and their presence in human urine of the nutmeg abuser was confirmed. The identified metabolites indicated that EL, MY, and SA were once and twice hydroxylated at the side chain. In addition, EL was O-demethylated at 2 positions followed by side chain hydroxylation. MY and SA were demethylenated and subsequently methylated. In the human urine sample, the following metabolites could be identified: O-demethyl elemicin, O-demethyl dihydroxy elemicin, demethylenyl myristicin, dihydroxy myristicin, and demethylenyl safrole. As in the human urine sample, neither amphetamine derivatives nor the main nutmeg ingredients could be detected in the rat urine samples. Finally, toxicologic detection of nutmeg abuse was possible by identification of the described metabolites of the EL, MY, and SA in urine applying the authors' systematic toxicologic analysis procedure using full-scan gas chromatography-mass spectrometry after acid hydrolysis, liquid-liquid extraction of analytes, and microwave-assisted acetylation of extracted analytes.

  15. Evaluation of a liver microfluidic biochip to predict in vivo clearances of seven drugs in rats.

    PubMed

    Baudoin, Regis; Legendre, Audrey; Jacques, Sebastien; Cotton, Jerome; Bois, Frederic; Leclerc, Eric

    2014-02-01

    We investigated metabolic clearances of phenacetin, midazolam, propranolol, paracetamol, tolbutamide, caffeine, and dextromethorphan by primary rat hepatocytes cultivated in microfluidic biochips. The levels of mRNA of the HNF4α, PXR, AHR, CYP3A1, and CYP1A2 genes were enhanced in the biochip cultures when compared with postextraction levels. We measured a high and rapid adsorption on the biochip walls and inside the circuit for dextromethorphan and midazolam, a moderate adsorption for phenacetin and propranolol, and a low adsorption for caffeine, tolbutamide, and paracetamol. Drug biotransformations were demonstrated by the formations of specific metabolites such as paraxanthyne (caffeine), paracetamol (phenacetin), 1-OH midazolam (midazolam), paracetamol sulfate (paracetamol and phenacetin), and dextrorphan (dextromethorphan). We used a pharmacokinetic model to estimate the adsorption and in vitro intrinsic drug clearance values. We calculated in vitro intrinsic clearance values of 0.5, 3, 12.5, 83, 100, 160, and 900 μL/min per 10(6) cells for the tolbutamide, caffeine, paracetamol, dextromethorphan, phenacetin, midazolam, and propranolol, respectively. A second model describing the liver as a well-stirred compartment predicted in vivo hepatic clearances of 0.1, 13.8, 30, 44.1, 61, 72, 85, and 61 mL/min per kg of body mass for the tolbutamide, caffeine, paracetamol, midazolam, dextromethorphan, phenacetin, and propranolol, respectively. These values appeared consistent with previously reported data. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  16. New Psychoactive Substances 3-Methoxyphencyclidine (3-MeO-PCP) and 3-Methoxyrolicyclidine (3-MeO-PCPy): Metabolic Fate Elucidated with Rat Urine and Human Liver Preparations and their Detectability in Urine by GC-MS, "LC-(High Resolution)-MSn" and "LC-(High Resolution)-MS/MS".

    PubMed

    A Michely, Julian A; Manier, Sascha K; Caspar, Achim T; Brandt, Simon D; Wallach, Jason; Maurer, Hans H

    2017-01-01

    3-Methoxyphencyclidine (3-MeO-PCP) and 3-methoxyrolicyclidine (3-MeOPCPy) are two new psychoactive substances (NPS). The aims of the present study were the elucidation of their metabolic fate in rat and pooled human liver microsomes (pHLM), the identification of the cytochrome P450 (CYP) isoenzymes involved, and the detectability using standard urine screening approaches (SUSA) after intake of common users' doses using gas chromatography-mass spectrometry (GC-MS), liquid chromatography-multi-stage mass spectrometry (LC-MSn), and liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS). For metabolism studies, rat urine samples were treated by solid phase extraction or simple precipitation with or without previous enzymatic conjugate cleavage. After analyses via LC-HR-MSn, the phase I and II metabolites were identified. Both drugs showed multiple aliphatic hydroxylations at the cyclohexyl ring and the heterocyclic ring, single aromatic hydroxylation, carboxylation after ring opening, O-demethylation, and glucuronidation. The transferability from rat to human was investigated by pHLM incubations, where Odemethylation and hydroxylation were observed. The involvement of the individual CYP enzymes in the initial metabolic steps was investigated after single CYP incubations. For 3-MeO-PCP, CYP 2B6 was responsible for aliphatic hydroxylations and CYP 2C19 and CYP 2D6 for O-demethylation. For 3-MeO-PCPy, aliphatic hydroxylation was again catalyzed by CYP 2B6 and O-demethylation by CYP 2C9 and CYP 2D6 Conclusions: As only polymorphically expressed enzymes were involved, pharmacogenomic variations might occur, but clinical data are needed to confirm the relevance. The detectability studies showed that the authors' SUSAs were suitable for monitoring the intake of both drugs using the identified metabolites. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. Application of a deuterium replacement strategy to modulate the pharmacokinetics of 7-(3,5-dimethyl-1H-1,2,4-triazol-1-yl)-3-(4-methoxy-2-methylphenyl)-2,6-dimethylpyrazolo[5,1-b]oxazole, a novel CRF1 antagonist.

    PubMed

    Stringer, Rowan A; Williams, Gareth; Picard, Franck; Sohal, Bindi; Kretz, Olivier; McKenna, Jeff; Krauser, Joel A

    2014-05-01

    Deuterium isotope effects were evaluated as a strategy to optimize the pharmacokinetics of 7-(3,5-dimethyl-1H-1,2,4-triazol-1-yl)-3-(4-methoxy-2-methylphenyl)-2,6-dimethylpyrazolo[5,1-b]oxazole (NVS-CRF38), a novel corticotropin-releasing factor receptor 1 (CRF1) antagonist. In an attempt to suppress O-demethylation of NVS-CRF38 without losing activity against the CRF1 receptor, the protons at the site of metabolism were replaced with deuterium. For in vitro and in vivo studies, intrinsic primary isotope effects (KH/KD) were determined by the ratio of intrinsic clearance (CLint) obtained for NVS-CRF38 and deuterated NVS-CRF38. In vitro kinetic isotope effects (KH/KD) were more pronounced when CLint values were calculated based on the rate of formation of the O-desmethyl metabolite (KH/KD ∼7) compared with the substrate depletion method (KH/KD ∼2). In vivo isotope effects were measured in rats after intravenous (1 mg/kg) and oral (10 mg/kg) administration. For both administration routes, isotope effects calculated from in vivo CLint corresponding to all biotransformation pathways were lower (KH/KD ∼2) compared with CLint values calculated from the O-demethylation reaction alone (KH/KD ∼7). Comparative metabolite identification studies were undertaken using rat and human microsomes to explore the potential for metabolic switching. As expected, a marked reduction of the O-demethylated metabolite was observed for NVS-CRF38; however, levels of NVS-CRF38's other metabolites increased, compensating to some extent for the isotope effect.

  18. Impact of ethnic origin and quinidine coadministration on codeine's disposition and pharmacodynamic effects.

    PubMed

    Caraco, Y; Sheller, J; Wood, A J

    1999-07-01

    CYP2D6 is polymorphically distributed so that in poor metabolizers enzyme activity is missing. The goal of this study was to compare the pharmacokinetics and pharmacodynamics of codeine with and without quinidine between Caucasian and Chinese extensive metabolizers of debrisoquin. Nine Caucasians and eight Chinese subjects received in random, double blind fashion, on two occasions, codeine 120 mg. with placebo or with quinidine 100 mg. Pharmacodynamic effects were determined over 6 h. Codeine-apparent clearance and partial metabolic clearance by O-demethylation were significantly greater in the Caucasian than in the Chinese subjects (1939 +/- 175 ml/min versus 1301 +/- 193 ml/min, p <.03 and 162.7 +/- 36.6 ml/min versus 52.7 +/- 12.7 ml/min, p <.02, respectively). Codeine's respiratory effects (except on resting ventilation) were significantly greater in the Caucasian than in the Chinese subjects (p <.05), but no interethnic differences were noted in codeine's effect on the digit symbol substitution test and pupillary ratio. No morphine or morphine metabolites were detected in plasma when codeine was coadministered with quinidine. Codeine O-demethylation was significantly reduced after quinidine in both ethnic groups; however, the absolute decrease was greater in Caucasians (115.8 +/- 25.9 ml/min versus 46.8 +/- 10.6 ml/min, respectively, p <.03). The diminished production of morphine after quinidine was associated in the Caucasians, but not in the Chinese, with a marked reduction in codeine's effects (p <.01). In conclusion, Chinese produce less morphine from codeine, exhibit reduced sensitivity to that morphine, and therefore might experience reduced analgesic effect in response to codeine. In addition, quinidine induced inhibition of codeine O-demethylation is ethnically dependent with the reduction being greater in Caucasians.

  19. Activation of G-proteins by morphine and codeine congeners: insights to the relevance of O- and N-demethylated metabolites at mu- and delta-opioid receptors.

    PubMed

    Thompson, Chad M; Wojno, Heidi; Greiner, Elisabeth; May, Everette L; Rice, Kenner C; Selley, Dana E

    2004-02-01

    Phenotypic differences in analgesic sensitivity to codeine (3-methoxymorphine) results from polymorphisms in cytochrome P450-2D6, which catalyzes O-demethylation of codeine to morphine. However, O-demethylation reportedly is not required for analgesic activity of the 7,8-saturated codeine congeners dihydrocodeine, hydrocodone, and oxycodone. This study determined the potency and efficacy of these compounds and their demethylated derivatives to stimulate mu- and delta-opioid receptor-mediated G-protein activation using agonist-stimulated guanosine 5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTP gamma S) binding. Results showed that 7,8-saturated codeine congeners were more efficacious than codeine in activating mu-receptors, but only dihydrocodeine was more efficacious at delta-receptors. Hydrocodone and oxycodone were approximately 10-fold more potent than codeine and dihydrocodeine at either receptor. Morphine-like compounds with a 3-hydroxy group were approximately 30- to 100-fold more potent than their 3-methoxy analogs at the mu-receptor, and these compounds generally exhibited greater efficacy (e.g., morphine produced 2-fold greater maximal stimulation than codeine). Removal of the N-methyl group did not affect efficacy or potency of codeine congeners to activate mu-receptors, whereas this modification generally increased efficacy but decreased potency of morphine congeners. At the delta receptor, morphine congeners showed greater potency and structure-dependent differences in efficacy compared with codeine congeners, whereas removal of the N-methyl group had effects similar to those observed at the mu-receptor. These results demonstrate that 7,8-saturated codeine congeners are more efficacious than codeine, which may explain their lack of requirement for 3-O-demethylation in vivo. Nonetheless, because all 7,8-saturated codeine congeners were significantly less potent than their morphine derivatives, further research is needed to understand the relationship

  20. ABCB1 genetic variant and its associated tacrolimus pharmacokinetics affect renal function in patients with rheumatoid arthritis.

    PubMed

    Naito, Takafumi; Mino, Yasuaki; Aoki, Yuki; Hirano, Kumi; Shimoyama, Kumiko; Ogawa, Noriyoshi; Kagawa, Yoshiyuki; Kawakami, Junichi

    2015-05-20

    This study aimed to evaluate the blood exposure of and clinical responses to tacrolimus based on genetic variants of CYP3A5 and ABCB1 in patients with rheumatoid arthritis. Seventy rheumatoid arthritis patients treated with oral tacrolimus once daily were enrolled. Blood concentrations of tacrolimus and its major metabolite 13-O-demethylate at 12h after dosing were determined. The relationships between the tacrolimus pharmacokinetics and efficacy, renal function, and CYP3A5 and ABCB1 genotypes were evaluated. Dose-normalized blood concentration of tacrolimus was significantly higher in the CYP3A5*3/*3 group than in the *1 allele carrier group. A lower metabolic ratio of 13-O-demethylate to tacrolimus was observed in the CYP3A5*3/*3 group. The ABCB1 3435TT group had higher dose-normalized blood concentrations of tacrolimus and 13-O-demethylate. The blood tacrolimus concentration was inversely correlated with the estimated glomerular filtration rate (eGFR). ABCB1 C3435T but not CYP3A5 genotype had decreased eGFR. Patients lacking the CYP3A5*3 allele had a higher incidence of tacrolimus withdrawal. CYP3A5*3 increased the blood exposure of tacrolimus through its metabolic reduction. ABCB1 C3435T led to a higher blood exposure of tacrolimus and its major metabolite. The ABCB1 genetic variant and its associated tacrolimus pharmacokinetics affected renal function in rheumatoid arthritis patients. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Mu receptor binding of some commonly used opioids and their metabolites

    SciTech Connect

    Chen, Zhaorong; Irvine, R.J. ); Somogyi, A.A.; Bochner, F. Royal Adelaide Hospital )

    1991-01-01

    The binding affinity to the {mu} receptor of some opioids chemically related to morphine and some of their metabolites was examined in rat brain homogenates with {sup 3}H-DAMGO. The chemical group at position 6 of the molecule had little effect on binding. Decreasing the length of the alkyl group at position 3 decreased the K{sub i} values (morphine < codeine < ethylmorphine < pholcodine). Analgesics with high clinical potency containing a methoxyl group at position 3 had relatively weak receptor binding, while their O-demethylated metabolites had much stronger binding. Many opioids may exert their pharmacological actions predominantly through metabolites.

  2. (-)-Arctigenin as a lead compound for anticancer agent.

    PubMed

    Chen, Gui-Rong; Li, Hong-Fu; Dou, De-Qiang; Xu, Yu-Bin; Jiang, Hong-Shuai; Li, Fu-Rui; Kang, Ting-Guo

    2013-01-01

    (-)-Arctigenin, an important active constituent of the traditional Chinese herb Fructus Arctii, was found to exhibit various bioactivities, so it can be used as a good lead compound for further structure modification in order to find a safer and more potent medicine. (-)-Arctigenin derivatives 1-5 of (-)-arctingen were obtained by modifying with ammonolysis at the lactone ring and sulphonylation at C (6') and C (6″) and O-demethylation at CH3O-C (3'), CH3O-C (3″) and CH3O-C (4″), and their anticancer bioactivities were examined.

  3. Microbial transformation of N-methylcolchiceinamide.

    PubMed Central

    Davis, P J

    1981-01-01

    Seventy-seven microorganisms were examined for their ability to metabolize the antineoplastic agent N-methylcolchiceinamide, an analog of colchicine. Five streptomycetes exhibited significant metabolism, and Streptomyces griseus NRRL B-599 completely converted the substrate to three metabolites. In preparative-scale studies, N-dealkylation resulted in the production of colchiceinamide, the major metabolite (65%), which was characterized by chemical, spectroscopic, and chromatographic comparisons with the standard compound. Two phenolic metabolites resulting from )-dealkylation were also isolated and identified as 2 and 3-O-demethyl-N-methylcolchiceinamide. PMID:6787979

  4. Neuropsychopharmacological understanding for therapeutic application of morphinans.

    PubMed

    Shin, Eun-Joo; Hong, Jau-Shyong; Kim, Hyoung-Chun

    2010-10-01

    Morphinans are a class of compounds containing the basic structure of morphine. It is well-known that morphinans possess diverse pharmacological effects on the central nervous system. This review will demonstrate novel neuroprotective effects of several morphinans such as, dextromethorphan, its analogs and naloxone on the models of multiple neurodegenerative disease by modulating glial activation associated with the production of a host of proinflammatory and neurotoxic factors, although dextromethorphan possesses neuropsychotoxic potentials. The neuroprotective effects and the therapeutic potential for the treatment of excitotoxic and inflammatory neurodegenerative diseases, and underlying mechanism of morphinans are discussed.

  5. Impact of CYP2D6 genotype on amitriptyline efficacy for the treatment of diabetic peripheral neuropathy: a pilot study.

    PubMed

    Chaudhry, Mamoonah; Alessandrini, Marco; Rademan, Jacobus; Dodgen, Tyren M; Steffens, Francois E; van Zyl, Danie G; Gaedigk, Andrea; Pepper, Michael S

    2017-04-01

    Therapy with low-dose amitriptyline is commonly used to treat painful diabetic peripheral neuropathy. There is a knowledge gap, however, regarding the role of variable CYP2D6-mediated drug metabolism and side effects (SEs). We aimed to generate pilot data to demonstrate that SEs are more frequent in patients with variant CYP2D6 alleles. To that end, 31 randomly recruited participants were treated with low-dose amitriptyline for painful diabetic peripheral neuropathy and their CYP2D6 gene sequenced. Patients with predicted normal or ultra-rapid metabolizer phenotypes presented with less SEs compared with individuals with decreased CYP2D6 activity. Hence, CYP2D6 genotype contributes to treatment outcome and may be useful for guiding drug therapy. Future investigations in a larger patient population are planned to support these preliminary findings.

  6. Physiologically Based Pharmacokinetic Predictions of Tramadol Exposure Throughout Pediatric Life: an Analysis of the Different Clearance Contributors with Emphasis on CYP2D6 Maturation.

    PubMed

    T'jollyn, Huybrecht; Snoeys, Jan; Vermeulen, An; Michelet, Robin; Cuyckens, Filip; Mannens, Geert; Van Peer, Achiel; Annaert, Pieter; Allegaert, Karel; Van Bocxlaer, Jan; Boussery, Koen

    2015-11-01

    This paper focuses on the retrospective evaluation of physiologically based pharmacokinetic (PBPK) techniques used to mechanistically predict clearance throughout pediatric life. An intravenous tramadol retrograde PBPK model was set up in Simcyp® using adult clearance values, qualified for CYP2D6, CYP3A4, CYP2B6, and renal contributions. Subsequently, the model was evaluated for mechanistic prediction of total, CYP2D6-related, and renal clearance predictions in very early life. In two in vitro pediatric human liver microsomal (HLM) batches (1 and 3 months), O-desmethyltramadol and N-desmethyltramadol formation rates were compared with CYP2D6 and CYP3A4 activity, respectively. O-desmethyltramadol formation was mediated only by CYP2D6, while N-desmethyltramadol was mediated in part by CYP3A4. Additionally, the clearance maturation of the PBPK model predictions was compared to two in vivo maturation models (Hill and exponential) based on plasma concentration data, and to clearance estimations from a WinNonlin® fit of plasma concentration and urinary excretion data. Maturation of renal and CYP2D6 clearance is captured well in the PBPK model predictions, but total tramadol clearance is underpredicted. The most pronounced underprediction of total and CYP2D6-mediated clearance was observed in the age range of 2-13 years. In conclusion, the PBPK technique showed to be a powerful mechanistic tool capable of predicting maturation of CYP2D6 and renal tramadol clearance in early infancy, although some underprediction occurs between 2 and 13 years for total and CYP2D6-mediated tramadol clearance.

  7. In vitro inhibition of methadone and oxycodone cytochrome P450-dependent metabolism: reversible inhibition by H2-receptor agonists and proton-pump inhibitors.

    PubMed

    Moody, David E; Liu, Fenyun; Fang, Wenfang B

    2013-10-01

    In vitro inhibition of oxycodone metabolism to noroxycodone and oxymorphone and R- and S-methadone metabolism to R- and S-2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) was measured for four H2-receptor antagonists and five proton-pump inhibitors (PPIs) using human liver microsomes (HLM) and cDNA-expressed human cytochrome P450s (rCYPs). Inhibitors were first incubated with HLM at three concentrations with and without preincubation of inhibitor, enzyme source and reducing equivalents to also screen for time-dependent inhibition (TDI). Cimetidine and famotidine (10-1,000 µM) inhibited all the four pathways >50%. Nizatidine and ranitidine did not. All the five PPIs (1-200 µM) inhibited one or more pathways >50%. Half maximal inhibitory concentrations (IC50s) were then determined using rCYPs. Cimetidine and famotidine both inhibited CYP3A4-mediated formation of noroxycodone and CYP2D6-mediated formation of oxymorphone, and famotidine inhibited CYP3A4-mediated formation of R- and S-EDDP, but IC50s were so high that only >10× therapeutic concentrations may have potential for reversible in vivo inhibition. The PPIs were more potent inhibitors; many have the potential for reversible in vivo inhibition at therapeutic concentrations. Omeprazole, esomeprazole and pantoprazole had greater effects on CYP3A4-mediated reactions, whereas lansoprazole was selective for CYP2D6-mediated formation of oxymorphone. Preincubation enhanced cimetidine inhibition of noroxycodone formation and rabeprazole inhibition of all pathways. Future studies will explore irreversible TDI.

  8. Metabolism of one-carbon compounds by the ruminal acetogan syntrophococcus sucromutans

    SciTech Connect

    Dore, J.; Bryant, M.P. )

    1990-04-01

    Syntrophococcus sucromutans is the predominant species capable of O demethylation of methoxylated lignin monoaromatic derivatives in the rumen. The enzymatic characterization of this acetogen indicated that it uses the acetyl coenzyme A (Woods) pathway. Cell extracts possess all the enzymes of the tetrahydrofolate pathway, as well as carbon monoxide dehydrogenase, at levels similar to those of other acetogens using this pathway. However, formate dehydrogenase could not be detected in cell extracts, whether formate or a methoxyaromatic was used as electron acceptor for growth of the cells on cellobiose. Labeled bicarbonate, formate, (1-{sup 14}C) pyruvate, and chemically synthesized O-(methyl-{sup 14}C) vanillate were used to further investigate the catabolism of one-carbon (C{sub 1}) compounds by using washed-cell preparations. The results were consistent with little or no contribution of formate dehydrogenase and pointed out some unique features. Conversion of formate to CO{sub 2} was detected, but labeled formate predominantly labeled the methyl group of acetate. Labeled CO{sub 2} readily exchanged with the carboxyl group of pyruvate but not with formate, and both labeled CO{sub 2} and pyruvate predominantly labeled the carboxyl group acetate. No CO{sub 2} was formed from O demethylation of vanillate, and the acetate produced was position labeled in the methyl group. The fermentation pattern and specific activities of products indicated a complete synthesis of acetate from pyruvate and the methoxyl group of vanillate.

  9. Metabolism of eupatilin in rats using liquid chromatography/electrospray mass spectrometry.

    PubMed

    Ji, Hye Young; Lee, Hye Won; Shim, Hyun Joo; Kim, Soon Hoe; Kim, Won Bae; Lee, Hye Suk

    2004-04-01

    Eupatilin (5,7-dihydroxy-3',4',6-trimethoxy flavone) is an active ingredient of an ethanol extract of Artemisia asiatica (DA-9601) that is used in the treatment of gastritis. In vitro and in vivo metabolism of eupatilin in the rats has been studied by LC-electrospray mass spectrometry. Rat liver microsomal incubation of eupatilin in the presence of NADPH and UDPGA resulted in the formation of four metabolites (M1-M4). M1, M2, M3 and M4 were tentatively identified as 3'- or 4'-O-demethyl-eupatilin glucuronide, eupatilin glucuronide, 6-O-demethyleupatilin and 3'- or 4'-O-demethyl-eupatilin, respectively. Those metabolites from in vitro study were also characterized in bile, plasma or urine samples after an intravenous administration of eupatilin to rats. In rat bile, plasma and urine samples, eupatilin glucuronide (M2) was a major metabolite, whereas M3, M4 and M4 glucuronide (M1) were the minor metabolites.

  10. Reactive Intermediates Produced from Metabolism of the Vanilloid Ring of Capsaicinoids by P450 Enzymes

    PubMed Central

    Reilly, Christopher A.; Henion, Fred; Bugni, Tim S.; Ethirajan, Manivannan; Stockmann, Chris; Pramanik, Kartick C.; Srivastava, Sanjay K.; Yost, Garold S.

    2012-01-01

    This study characterized electrophilic and radical products derived from metabolism of capsaicin by cytochrome P450 and peroxidase enzymes. Multiple glutathione and β-mercaptoethanol conjugates (a.k.a., adducts), derived from trapping of quinone methide and quinone intermediates of capsaicin, its analogue nonivamide, and O-demethylated and aromatic hydroxylated metabolites thereof, were produced by human liver microsomes and individual recombinant human P450 enzymes. Conjugates derived from concomitant dehydrogenation of the alkyl terminus of capsaicin, were also characterized. Modifications to the 4-OH substituent of the vanilloid ring of capsaicinoids largely prevented the formation of electrophilic intermediates, consistent with the proposed structures and mechanisms of formation for the various conjugates. 5,5’-Dicapsaicin, presumably arising from bi-molecular coupling of free radical intermediates, was also characterized. Finally, the analysis of hepatic glutathione conjugates and urinary N-acetylcysteine conjugates from mice dosed with capsaicin confirmed the formation of glutathione conjugates of O-demethylated, quinone methide, and 5-OH-capsaicin in vivo. These data demonstrated that capsaicin and structurally similar analogues are converted to reactive intermediates by certain P450 enzymes, which may partially explain conflicting reports related to the cytotoxic, pro-carcinogenic, and chemoprotective effects of capsaicinoids in different cells and/or organ systems. PMID:23088752

  11. Metabolic Profile of Skimmianine in Rats Determined by Ultra-Performance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Tandem Mass Spectrometry.

    PubMed

    Huang, Aihua; Xu, Hui; Zhan, Ruoting; Chen, Weiwen; Liu, Jiawei; Chi, Yuguang; Chen, Daidi; Ji, Xiaoyu; Luo, Chaoquan

    2017-03-23

    Skimmianine is a furoquinoline alkaloid present mainly in the Rutaceae family. It has been reported to have analgesic, antispastic, sedative, anti-inflammatory, and other pharmacologic activities. Despite its critical pharmacological function, its metabolite profiling is still unclear. In this study, the in vivo metabolite profiling of skimmianine in rats was investigated using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS). The metabolites were predicted using MetabolitePilot(TM) software. These predicted metabolites were further analyzed by MS² spectra, and compared with the detailed fragmentation pathway of the skimmianine standard and literature data. A total of 16 metabolites were identified for the first time in rat plasma, urine, and feces samples after oral administration of skimmianine. Skimmianine underwent extensive Phase I and Phase II metabolism in rats. The Phase I biotransformations of skimmianine consist of epoxidation of olefin on its furan ring (M1) followed by the hydrolysis of the epoxide ring (M4), hydroxylation (M2, M3), O-demethylation (M5-M7), didemethylation (M14-M16). The Phase II biotransformations include glucuronide conjugation (M8-M10) and sulfate conjugation (M11-M13). The epoxidation of 2,3-olefinic bond followed by the hydrolysis of the epoxide ring and O-demethylation were the major metabolic pathways of skimmianine. The results provide key information for understanding the biotransformation processes of skimmianine and the related furoquinoline alkaloids.

  12. The influence of pharmacogenetics on opioid analgesia: studies with codeine and oxycodone in the Sprague-Dawley/Dark Agouti rat model.

    PubMed

    Cleary, J; Mikus, G; Somogyi, A; Bochner, F

    1994-12-01

    In the Sprague-Dawley (SD) rat, the O-demethylation of codeine to morphine is catalyzed by cytochrome P4502D1 (CYP2D1), which is absent in the female Dark Agouti (DA) rat. Oxycodone is similar in structure to codeine but, in contrast, has an analgesic potency in humans similar to morphine. The aim of the study was to test whether the DA rat and the SD rat pretreated with the CYP2D1 inhibitor quinine showed attenuation in analgesia to codeine and oxycodone. With the use of the tail flick model, dose-response curves were constructed to codeine, morphine, oxycodone and oxymorphone (the O-demethylated metabolite of oxycodone) in both rat strains. Codeine did not induce analgesia in the DA rat and there was a 60% reduction in codeine analgesia in the SD rat pretreated with quinine in comparison to the untreated SD rat. In the DA rat, the ED50 to oxycodone was increased 10-fold but there was a significant (P = .0001) prolongation in the duration of analgesia in comparison to that in the untreated SD rat. In the quinine-pretreated SD rat, there was no reduction in oxycodone analgesia but the duration of analgesia was also prolonged. It was concluded that 1) codeine-mediated analgesia requires the formation of morphine through the functional activity of CYP2D1 and 2) oxycodone-mediated analgesia may only be partly dependent on CYP2D1.

  13. Disposition, metabolism and mass balance of [14C]apremilast following oral administration

    PubMed Central

    Hoffmann, Matthew; Kumar, Gondi; Schafer, Peter; Cedzik, Dorota; Capone, Lori; Kei-Fong, Lai; Gu, Zheming; Heller, Dennis; Feng, Hao; Surapaneni, Sekhar; Laskin, Oscar; Wu, Anfan

    2011-01-01

    Apremilast is a novel, orally available small molecule that specifically inhibits PDE4and thus modulates multiple pro- and anti-inflammatory mediators, and is currently under clinical development for the treatment of psoriasis and psoriatic arthritis.The pharmacokinetics and disposition of [14C]apremilastwas investigated following a single oral dose (20 mg, 100 uCi) to healthy male subjects. Approximately 58% of the radioactive dose was excreted in urine, while faeces contained 39%. Mean Cmax, AUC0 and tmax values for apremilast in plasma were 333 ng/mL, 1970 ng*h/mL and 1.5 h. Apremilast was extensively metabolized via multiple pathways, with unchanged drug representing 45% of the circulating radioactivity and <7% of the excreted radioactivity. The predominant metabolite was O-desmethyl apremilast glucuronide, representing 39% of plasma radioactivity and 34% of excreted radioactivity. The only other radioactive components that represented >4%of the excreted radioactivity were O-demethylated apremilast and its hydrolysis product. Additional minor circulating and excreted compounds were formed via O-demethylation, O-deethylation, N-deacetylation, hydroxylation, glucuronidation and/or hydrolysis. The major metabolites were at least 50-fold less pharmacologically active than apremilast. Metabolic clearance of apremilast was the major route of elimination, while non-enzymatic hydrolysis and excretion of unchanged drug were involved to a lesser extent. PMID:21859393

  14. VA and DoD Operating as One

    DTIC Science & Technology

    2011-01-25

    Dextromethorphan Hydrobromide U UD ŕ RFO DoD Menthol + Cetylpyridinium Chloride, lozenge, I USE AS DIRECTED FOR COUGH I DoD ACETAMINOPHEN. 325 MG. TABLET...ORAL TAKE 1·2 TABS EVERY 4-6HOUR DoD BISMUTH SU8SAUCYLATE. 262 MG. TAB C~ CHEW 2 TABS EVERY 1/2 HOUR DoD Menthol + Cetylpyridinium Chloride

  15. 75 FR 23782 - Drug Safety and Risk Management Advisory Committee; Notice of Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-04

    ... HUMAN SERVICES Food and Drug Administration Drug Safety and Risk Management Advisory Committee; Notice... be open to the public. Name of Committee: Drug Safety and Risk Management Advisory Committee. General... risks of dextromethorphan use as a cough suppressant in prescription and nonprescription drug products...

  16. Cough and Cold Medicine Abuse (For Parents)

    MedlinePlus

    ... kids from intentionally overdosing on cough and cold medicine. Why Do Kids Abuse Cough and Cold Remedies? Before the U.S. Food and Drug Administration (FDA) replaced the narcotic codeine with dextromethorphan as an over-the-counter (OTC) cough suppressant in the 1970s, teens were ...

  17. Crystal structures of bis-[(9S,13S,14S)-3-meth-oxy-17-methyl-morphinanium] tetra-chlorido-cobaltate and tetra-chlorido-cuprate.

    PubMed

    Gauchat, Eric; Nazarenko, Alexander Y

    2017-01-01

    (9S,13S,14S)-3-Meth-oxy-17-methyl-morphinan (dextromethorphan) forms two isostructural salts with (a) tetra-chlorido-cobaltate, namely bis-[(9S,13S,14S)-3-meth-oxy-17-methyl-morphinanium] tetra-chlorido-cobaltate, (C18H26NO)2[CoCl4], and (b) tetra-chlorido-cuprate, namely bis-[(9S,13S,14S)-3-meth-oxy-17-methyl-morphinanium] tetra-chlorido-cuprate, (C18H26NO)2[CuCl4]. The distorted tetra-hedral anions are located on twofold rotational axes. The dextromethorphan cation can be described as being composed of two ring systems, a tetra-hydro-naphthalene system A+B and a deca-hydro-isoquinolinium subunit C+D, that are nearly perpendicular to one another: the angle between mean planes of the A+B and C+D moieties is 78.8 (1)° for (a) and 79.0 (1)° for (b). Two symmetry-related cations of protonated dextromethorphan are connected to the tetra-chlorido-cobaltate (or tetra-chlorido-cuprate) anions via strong N-H⋯Cl hydrogen bonds, forming neutral ion associates. These associates are packed in the (001) plane with no strong attractive bonding between them. Both compounds are attractive crystalline forms for unambiguous identification of the dextromethorphan and, presumably, of its optical isomer, levomethorphan.

  18. Evaluation of cytochrome P450 2D6 phenotyping in healthy adult Western Indians.

    PubMed

    Gogtay, Nithya J; Mali, Nitin B; Iyer, Krishna; Kadam, Prashant P; Sridharan, Kannan; Shrimal, Divya; Thatte, Urmila M

    2014-01-01

    Cytochrome P450 2D6 (CYP2D6) metabolizes around 25% of the drugs used in therapeutics and different polymorphisms have been identified in various populations. This study aimed at finding the prevalence of CYP2D6 polymorphisms using dextromethorphan as a probe drug. Healthy participants were administered 60 mg dextromethorphan after an overnight fast and 5 ml of blood was collected 3 h postdose. A validated laboratory method was used to measure both dextromethorphan and its active metabolite, dextrorphan from plasma. Metabolic ratio (MR) of dextromethorphan to dextrorphan was calculated for each of the participants. Probit analysis was done and antimode was defined. Individuals with log MR equal to or higher than the antimode were classified as poor metabolizers (PMs) and those with values less than antimode were categorized as extensive metabolizers (EMs). Data from a total of 149 participants were evaluated and the median (range) of MR was 0.25 (0.03-3.01). The polynomial equation obtained in probit analysis gave an antimode for MR of 1.39. Five (3.36%) participants were PMs and 144 (96.64%) were found to be EMs. One participant had reported mild drowsiness 2 h postdose that subsided spontaneously without any intervention. The prevalence of CYP2D6 polymorphism in Western Indian population is low (3.36%) and is similar to other populations.

  19. Photochemical N-demethylation of alkaloids.

    PubMed

    Ripper, J A; Tiekink, E R; Scammells, P J

    2001-02-26

    Certain alkaloids were observed to undergo N-demethylation processes under photochemical conditions. Tropine, acetyltropine, tropinone, and atropine were cleanly N-demethylated upon treatment with tetraphenylporphin, oxygen, and light. Dextromethorphan also underwent a N-demethylation reaction, but reacted further to afford an imine. In contrast, 14-acyloxycodeinones underwent a photochemically induced tandem N-demethylation acyl migration.

  20. Epidemiology of Toxicological Factors in Civil Aviation Accident Pilot Fatalities, 1999-2003

    DTIC Science & Technology

    2005-11-01

    central nervous system (5−7). For example, fi rst-generation antihistaminics—brompheniramine, chlorpheniramine, diphenhydramine, and doxylamine — cause...11 18 31 Dextromethorphan/Metabolite(s) 1 7 9 20 Doxylamine 0 8 11 19 Ephedrine 9 24 41 74 Meclizine 0 0 1 1 (–)-Methamphetamine 1 4 3 8

  1. 76 FR 33727 - Proposed Collection; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-09

    ... Form; and OMB Number: A Trial of Dextromethorphan and Naltrexone for Gulf War illness. Associated Form... collection requirement is necessary in order to contact veterans of the Gulf War to see if they are interested and qualified to participate in a research study. Affected Public: Gulf War Veterans....

  2. Antitussives and substance abuse

    PubMed Central

    Burns, Jarrett M; Boyer, Edward W

    2013-01-01

    Abuse of antitussive preparations is a continuing problem in the United States and throughout the world. Illicit, exploratory, or recreational use of dextromethorphan and codeine/promethazine cough syrups is widely described. This review describes the pharmacology, clinical effects, and management of toxicity from commonly abused antitussive formulations. PMID:24648790

  3. Codeine consumption from over-the-counter anti-cough syrup in Taiwan: A useful indicator for opioid abuse.

    PubMed

    Lo, Ming-Yu; Ong, Ming Wei; Lin, Jaung-Geng; Sun, Wei-Zen

    2015-12-01

    Over-the-counter (OTC) anti-cough preparations, many of which contain codeine (an opioid) or dextromethorphan (an opioid-like), are widely available in Taiwan and thus susceptible to overuse or abuse. We aimed to investigate whether opioids in the form of OTC antitussives play a significant role in medication abuse in Taiwan. Data on the consumption of codeine and dextromethorphan in antitussives and expectorants from 2011 through 2014 in Taiwan were provided by IMS Health (Intercontinental Marketing Services). These data were then analyzed for trends and variance according to availability, as prescription or OTC, and according to drug type, as codeine or dextromethorphan, in order to form four primary sectors under opioid-containing anti-cough syrup consumption. From 2011 to 2014, use of opioid-containing cough syrup fluctuated between 6% and 9% from year to year for all cough syrup consumption, with an overall declining trend (11.3% per year relative to 2011). Within the underlying sectors, mean consumption for prescription dextromethorphan (61.4%) outstripped the other three sectors, followed in decreasing order by OTC codeine (20.2%), OTC dextromethorphan (10.5%), and prescription codeine (8.0%). However, movement in consumption corresponded mainly with OTC codeine, whose variance greatly exceeded that of the other sectors, which follow in order of decreasing variance as OTC dextromethorphan, prescription dextromethorphan, and prescription codeine. The fairly low and stable consumption of prescription codeine suggested that physicians in Taiwan were careful in prescribing codeine, and that the medical demand for codeine was stable. The large variance in OTC codeine consumption suggested that a minority of consumers purchased significant quantities of codeine for non-medical purposes. Although opioids in cough syrup were not a large part of overall consumption and thus not widely abused, the data revealed that OTC codeine-containing cough syrup may serve as an

  4. Characterization of the active site properties of CYP4F12.

    PubMed

    Eksterowicz, John; Rock, Dan A; Rock, Brooke M; Wienkers, Larry C; Foti, Robert S

    2014-10-01

    Cytochrome P450 4F12 is a drug-metabolizing enzyme that is primarily expressed in the liver, kidney, colon, small intestine, and heart. The properties of CYP4F12 that may impart an increased catalytic selectivity (decreased promiscuity) were explored through in vitro metabolite elucidation, kinetic isotope effect experiments, and computational modeling of the CYP4F12 active site. By using astemizole as a probe substrate for CYP4F12 and CYP3A4, it was observed that although CYP4F12 favored astemizole O-demethylation as the primary route of metabolism, CYP3A4 was capable of metabolizing astemizole at multiple sites on the molecule. Deuteration of astemizole at the site of O-demethylation resulted in an isotope effect of 7.1 as well as an 8.3-fold decrease in the rate of clearance for astemizole by CYP4F12. Conversely, although an isotope effect of 3.8 was observed for the formation of the O-desmethyl metabolite when deuterated astemizole was metabolized by CYP3A4, there was no decrease in the clearance of astemizole. Development of a homology model of CYP4F12 based on the crystal structure of cytochrome P450 BM3 predicted an active site volume for CYP4F12 that was approximately 76% of the active site volume of CYP3A4. As predicted, multiple favorable binding orientations were available for astemizole docked into the active site of CYP3A4, but only a single binding orientation with the site of O-demethylation oriented toward the heme was identified for CYP4F12. Overall, it appears that although CYP4F12 may be capable of binding similar ligands to other cytochrome P450 enzymes such as CYP3A4, the ability to achieve catalytically favorable orientations may be inherently more difficult because of the increased steric constraints of the CYP4F12 active site. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  5. Influence of amino acid residue 374 of cytochrome P-450 2D6 (CYP2D6) on the regio- and enantio-selective metabolism of metoprolol.

    PubMed Central

    Ellis, S W; Rowland, K; Ackland, M J; Rekka, E; Simula, A P; Lennard, M S; Wolf, C R; Tucker, G T

    1996-01-01

    Cytochrome P-450 2D6 (CYP2D6) is an important human drug-metabolizing enzyme responsible for the oxidation of more than 30 widely used therapeutic agents. The enzymes encoded by the published genomic [Kimura, Umeno, Skoda, Meyer and Gonzalez (1989) Am. J. Hum. Genet. 45, 889-904] and cDNA [Gonzalez, Skoda, Kimura, Umeno, Zanger, Nebert, Gelboin, Hardwick and Meyer (1988) Nature 331, 442-446] sequences of CYP2D6, and presumed to represent wild-type sequences, differ at residue 374 and encode valine (CYP2D6-Val) and methionine (CYP2D6-Met) respectively. The influence of this amino acid difference on cytochrome P-450 expression, ligand binding, catalysis and stereoselective oxidation of metoprolol was investigated by the heterologous expression of the corresponding cDNAs in the yeast Saccharomyces cerevisiae. The level of expression of apo- and holo-protein was similar with each form of CYP2D6 cDNA, and the binding affinities of a series of ligands to CYP2D6-Val and CYP2D6-Met were identical. The enantioselective O-demethylation and alpha-hydroxylation of metoprolol were also similar with each form of CYP2D6, O-demethylation being R-(+)- enantioselective (CYP2D6-Val: R/S, 1.6; CYP2D6-Met: R/S, 1.4), whereas alpha-hydroxylation showed a preference for S-(-)-metoprolol (CYP2D6-Val: R/S, 0.7; CYP2D6-Met: R/S, 0.8). However, although the favoured regiomer overall was O-demethylmetoprolol (ODM), the regioselectivity for O-demethylation of each metoprolol enantiomer was significantly greater for CYP2D6-Val [R-(+)-: ODM/alpha-hydroxymetoprolol (alpha OH), 5.9; S-(-)-: ODM/alpha OH, 2.5) than that observed for CYP2D6-Met [R-(+)-: ODM/alpha OH, 2.2; S-(-)-: ODM/alpha OH, 1.4]. The stereoselective properties of CYP2D6-Val were consistent with those observed for CYP2D6 in human liver microsomes. The difference in the stereoselective properties of CYP2D6-Val and CYP2D6-Met were rationalized with respect to a homology model of the active site of CYP2D6 based on an alignment with

  6. Effect of sodium ozagrel on the activity of rat CYP2D6.

    PubMed

    Wu, Hong; Yu, Weijiang; Huang, Lijun; Wang, Jing; Tang, Xiaobo; Yang, Wei; Liu, Yan; Yu, Huiyan; Zhu, Daling

    2007-11-14

    The aim of the study was to investigate the influence of sodium ozagrel on CYP2D6 (cytochromeP450 2D6) activity. The studies were performed with rat urine and liver microsomes and chemical inhibitors. The metabolism of dextromethorphan (dextrophan/dextromethorphan, dextrophan is a metabolite of dextromethorphan) and phenacetin (paracetamol/phenacetin, paracetamol is a metabolites of phenacetin) was used as probe to measure CYP2D6 and CYP1A2 (cytochromeP450 1A2) activity, respectively, determined by high-performance liquid chromatography (HPLC). The results showed that the metabolism of dextrophan/dextromethorphan in the sodium ozagrel-treated group (37 mg/kg) was higher than that of the control (P<0.05/6) in both in vivo and in vitro studies (r=0.9811). The rate of dextromethorphan metabolism was inhibited by sodium ozagrel and cimetidine in rat liver microsomes prepared from sodium ozagrel-treated rats and control rats group (sodium ozagrel IC(50)=26.5 microM, cimetidine IC(50)=86.3 microM in sodium ozagrel-treated group; sodium ozagrel IC(50)=13.9 microM, cimetidine IC(50)=24.8 microM in control group). The inhibitory effect of sodium ozagrel on CYP2D6 activity was noncompetitive with dextromethorphan with a K(i) of 324.94 microM. Kinetic parameters of the reactions were established by using Lineweaver-Burk with K(m)=0.67 mM and V(max)=2.13 pm/min/mg protein for the sodium ozagrel-treated group and K(m)=0.29 mM, and V(max)=0.91 pm/min/mg protein for the control group, respectively. The expression of CYP2D6 protein in the treated group was higher than that of the control group, as determined by Western blotting. The activity and expression of CYP1A2 did not show obvious differences in the control group and sodium ozagrel treated group. In conclusion, sodium ozagrel metabolism in rats is mediated primarily through CYP2D6, and sodium ozagrel can induce CYP2D6 activity.

  7. Cellular reactions of O6-methylguanine, a product of some alkylating carcinogens

    PubMed Central

    Miller, Carolyn Thatcher; Lawley, Philip D.; Shah, Sudhirkumar A.

    1973-01-01

    Cultures of a purine-requiring mutant of Chinese hamster ovary cells (CHO-104b), randomly bred hamster embryo cells, or Escherichia coli Bs−1 were treated with non-toxic doses of 3H-labelled O6-methylguanine. DNA and RNA were isolated and subjected to enzymic digestion to nucleosides at pH8. The products of digestion were analysed by ion-exchange chromatography on columns of Dowex 50 (NH4+ form) at pH8.9. No 3H-labelled O6-methylguanosine was detected in nucleic acid digests. 3H-labelled O6-methylguanine was O-demethylated yielding [3H]guanine in CHO-104b cells. Radioactivity in nucleic acid digests was associated with thymidine, guanosine, deoxyguanosine and an unidentified early-eluting product. Reports of similar unidentified products from nucleic acids labelled with various agents are discussed. PMID:4590203

  8. Maduramicin. alpha. : Characterization of sup 14 C-derived residues in turkey excreta

    SciTech Connect

    Stout, S.J.; daCunha, A.R.; Lee, A. ); Jinn Wu; King, K.G. )

    1991-02-01

    Maduramicin {alpha}, a highly potent polyether ionophore antibiotic for preventing coccidiosis in poultry, is passed predominantly in turkey excreta following oral feeding. Following isolation and purification, the turkey excreta metabolites were characterized primarily by liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry. Maduramicin {alpha} and its metabolites generate a characteristic pair of ions corresponding to (M + NH{sub 4}){sup +} and (M + Na){sup +} which assist in differentiating the metabolites from matrix coextractives. These two ions also fragment differently in tandem mass spectrometry, thus providing structural information for characterizing the nature of unknown metabolites. The primary metabolic pathway of maduramicin {alpha} in the turkey is O-demethylation at one or more of the methoxy groups. Hydroxylation and glucuronide conjugation are minor secondary metabolic processes.

  9. Metabolism in the rat of some pyrazine derivatives having flavour importance in foods.

    PubMed

    Hawksworth, G; Scheline, R R

    1975-07-01

    1. The metabolism of several alkyl- and alkoxy-substituted pyrazines in the rat has been investigated. 2. Alkyl substituted compounds were oxidized to the corresponding acids which were excreted in the urine as such or as their glycine cojugates. The extent of oxidation was reduced when two adjacent alkyl groups were present. In the latter case ring hydroxylation also occurred. Methoxy-substituted pyrazines underwent O-demethylation and ring hydroxylation. 3. Little or no biliary excretion of the pyrazines or their metabolites occurred. 4. Some preliminary results on the metabolism of 2-isobutyl-3-methoxy-pyrazine (the major characteristic flavour component of bell pepper) have been obtained. 5. For comparative purposes the metabolism of some similarly substituted pyridines was investigated.

  10. Papaverine 7-O-demethylase, a novel 2-oxoglutarate/Fe(2+)-dependent dioxygenase from opium poppy.

    PubMed

    Farrow, Scott C; Facchini, Peter J

    2015-09-14

    Opium poppy (Papaver somniferum) produces several pharmacologically important benzylisoquinoline alkaloids including the vasodilator papaverine. Pacodine and palaudine are tri-O-methylated analogs of papaverine, which contains four O-linked methyl groups. However, the biosynthetic origin of pacodine and palaudine has not been established. Three members of the 2-oxoglutarate/Fe(2+)-dependent dioxygenases (2ODDs) family in opium poppy display widespread O-dealkylation activity on several benzylisoquinoline alkaloids with diverse structural scaffolds, and two are responsible for the antepenultimate and ultimate steps in morphine biosynthesis. We report a novel 2ODD from opium poppy catalyzing the efficient substrate- and regio-specific 7-O-demethylation of papaverine yielding pacodine. The occurrence of papaverine 7-O-demethylase (P7ODM) expands the enzymatic scope of the 2ODD family in opium poppy and suggests an unexpected biosynthetic route to pacodine.

  11. Mu receptor binding of some commonly used opioids and their metabolites.

    PubMed

    Chen, Z R; Irvine, R J; Somogyi, A A; Bochner, F

    1991-01-01

    The binding affinity to the mu receptor of some opioids chemically related to morphine and some of their metabolites was examined in rat brain homogenates with 3H-DAMGO. The chemical group at position 6 of the molecule had little effect on binding (e.g. morphine-6-glucuronide Ki = 0.6 nM; morphine = 1.2 nM). Decreasing the length of the alkyl group at position 3 decreased the Ki values (morphine less than codeine less than ethylmorphine less than pholcodine). Analgesics with high clinical potency containing a methoxyl group at position 3 (e.g. hydrocodone, Ki = 19.8 nM) had relatively weak receptor binding, whilst their O-demethylated metabolites (e.g. hydromorphone, Ki = 0.6 nM) had much stronger binding. Many opioids may exert their pharmacological actions predominantly through metabolites.

  12. Biobased Epoxy Nanocomposites Derived from Lignin-Based Monomers.

    PubMed

    Zhao, Shou; Abu-Omar, Mahdi M

    2015-07-13

    Biobased epoxy nanocomposites were synthesized based on 2-methoxy-4-propylphenol (dihydroeugenol, DHE), a molecule that has been obtained from the lignin component of biomass. To increase the content of hydroxyl groups, DHE was o-demethylated using aqueous HBr to yield propylcatechol (DHEO), which was subsequently glycidylated to epoxy monomer. Optimal conditions in terms of yield and epoxy equivalent weight were found to be 60 °C with equal NaOH/phenolic hydroxyl molar ratio. The structural evolution from DHE to cured epoxy was followed by (1)H NMR and Fourier transform infrared spectroscopy. The nano-montmorillonite modified DHEO epoxy exhibited improved storage modulus and thermal stability as determined from dynamic mechanical analysis and thermogravimetric analysis. This study widens the synthesis routes of biobased epoxy thermosets from lignin-based molecules.

  13. Investigation of the anti-angiogenesis effects induced by deoxypodophyllotoxin-5-FU conjugate C069 against HUVE cells.

    PubMed

    Xiang, Rong; Guan, Xiao-Wen; Hui, Ling; Jin, Yong-Xin; Chen, Shi-Wu

    2017-02-15

    We have found that the deoxypodophyllotoxin-5-fluorouracil conjugate, 4'-O-demethyl-4-deoxyppodophyllotoxin-4'-yl 4-((6-(2-(5-fluorouracil-yl)acetamido) hexyl)amino)-4-oxobutanoate (C069), possessed superior cytotoxicities and less toxicity compared with etoposide. In this paper, the anti-angiogenic and vascular disrupting activities of C069 were examined with several in vitro and in vivo models. First, we demonstrated that C069 significantly inhibited the proliferation, migration, tube formation and disrupted the formed tube-like structures of HUVE cells, and inhibited angiogenesis in chicken chorioallantoic membrane assay. Furthermore, we found that C069 inhibited tube formation of HUVE cells by down-regulating the MMP-2, MMP-9, and phosphorylation of Akt and β-catenin. These results provided the initial evidence that C069 exerts potent anti-angiogenic and vascular disrupting effects. Copyright © 2017. Published by Elsevier Ltd.

  14. Methane production from coal by a single methanogen

    NASA Astrophysics Data System (ADS)

    Mayumi, Daisuke; Mochimaru, Hanako; Tamaki, Hideyuki; Yamamoto, Kyosuke; Yoshioka, Hideyoshi; Suzuki, Yuichiro; Kamagata, Yoichi; Sakata, Susumu

    2016-10-01

    Coal-bed methane is one of the largest unconventional natural gas resources. Although microbial activity may greatly contribute to coal-bed methane formation, it is unclear whether the complex aromatic organic compounds present in coal can be used for methanogenesis. We show that deep subsurface-derived Methermicoccus methanogens can produce methane from more than 30 types of methoxylated aromatic compounds (MACs) as well as from coals containing MACs. In contrast to known methanogenesis pathways involving one- and two-carbon compounds, this “methoxydotrophic” mode of methanogenesis couples O-demethylation, CO2 reduction, and possibly acetyl-coenzyme A metabolism. Because MACs derived from lignin may occur widely in subsurface sediments, methoxydotrophic methanogenesis would play an important role in the formation of natural gas not limited to coal-bed methane and in the global carbon cycle.

  15. Use of 13C NMR and ftir for elucidation of degradation pathways during natural litter decomposition and composting I. early stage leaf degradation

    USGS Publications Warehouse

    Wershaw, R. L.; Leenheer, J.A.; Kennedy, K.R.; Noyes, T.I.

    1996-01-01

    Oxidative degradation of plant tissue leads to the formation of natural dissolved organic carbon (DOC) and humus. Infrared (IR) and 13C nuclear magnetic resonance (NMR) spectrometry have been used to elucidate the chemical reactions of the early stages of degradation that give rise to DOC derived from litter and compost. The results of this study indicate that oxidation of the lignin components of plant tissue follows the sequence of O-demethylation, and hydroxylation followed by ring-fission, chain-shortening, and oxidative removal of substituents. Oxidative ring-fission leads to the formation of carboxylic acid groups on the cleaved ends of the rings and, in the process, transforms phenolic groups into aliphatic alcoholic groups. The carbohydrate components are broken down into aliphatic hydroxy acids and aliphatic alcohols.

  16. Methane production from coal by a single methanogen.

    PubMed

    Mayumi, Daisuke; Mochimaru, Hanako; Tamaki, Hideyuki; Yamamoto, Kyosuke; Yoshioka, Hideyoshi; Suzuki, Yuichiro; Kamagata, Yoichi; Sakata, Susumu

    2016-10-14

    Coal-bed methane is one of the largest unconventional natural gas resources. Although microbial activity may greatly contribute to coal-bed methane formation, it is unclear whether the complex aromatic organic compounds present in coal can be used for methanogenesis. We show that deep subsurface-derived Methermicoccus methanogens can produce methane from more than 30 types of methoxylated aromatic compounds (MACs) as well as from coals containing MACs. In contrast to known methanogenesis pathways involving one- and two-carbon compounds, this "methoxydotrophic" mode of methanogenesis couples O-demethylation, CO2 reduction, and possibly acetyl-coenzyme A metabolism. Because MACs derived from lignin may occur widely in subsurface sediments, methoxydotrophic methanogenesis would play an important role in the formation of natural gas not limited to coal-bed methane and in the global carbon cycle.

  17. Metabolic pathways of the psychotropic-carboline alkaloids, harmaline and harmine, by liquid chromatography/mass spectrometry and NMR spectroscopy.

    PubMed

    Zhao, Ting; Zheng, Shan-Song; Zhang, Bin-Feng; Li, Yuan-Yuan; Bligh, S W Annie; Wang, Chang-Hong; Wang, Zheng-Tao

    2012-09-15

    The β-carboline alkaloids, harmaline and harmine, are present in hallucinogenic plants Ayahuasca and Peganum harmala, and in a variety of foods. In order to establish the metabolic pathway and bioactivities of endogenous and xenobiotic bioactive β-carbolines, high-performance liquid chromatography, coupled with mass spectrometry, was used to identify these metabolites in human liver microsomes (HLMs) in vitro and in rat urine and bile samples after oral administration of the alkaloids. Three metabolites of harmaline and two of harmine were found in the HLMs. Nine metabolites for harmaline and seven metabolites for harmine, from the rat urine and bile samples, were identified. Among them, four in vivo metabolites were isolated and fully characterised by NMR analysis. For the first time, harmaline is shown transforming to harmine by oxidative dehydrogenation in rat. Five metabolic pathways were therefore proposed, namely, oxidative dehydrogenation, 7-O-demethylation, hydroxylation, O-glucuronide conjugation and O-sulphate conjugation.

  18. Ethylene glycol monomethyl ether and propylene glycol monomethyl ether: metabolism, disposition, and subchronic inhalation toxicity studies

    SciTech Connect

    Miller, R.R.; Hermann, E.A.; Young, J.T.; Landry, T.D.; Calhoun, L.L.

    1984-08-01

    Short-term and subchronic vapor inhalation studies have shown that there are pronounced differences in the toxicological properties of ethylene glycol monomethyl ether (EGME) and propylene glycol monomethyl ether (PGME). Overexposure to EGME has resulted in adverse effects on testes, bone marrow and lymphoid tissues in laboratory animals. PGME does not affect these tissues, and instead, overexposure to PGME has been associated with increases in liver weight and central nervous system depression. EGME is primarily oxidized to methoxyacetic acid in male rats, while PGME apparently undergoes O-demethylation to form propylene glycol. Since methoxyacetic acid has been shown to have the same spectrum of toxicity as EGME in male rats, the observed differences in the toxicological properties of EGME and PGME are thought to be due to the fact that the two materials are biotransformed via different routes to different types of metabolites. 6 references, 3 figures, 12 tables.

  19. Separation of cold medicine ingredients by capillary electrophoresis.

    PubMed

    Suntornsuk, L

    2001-01-01

    This study demonstrates the separation of cold medicine ingredients (e.g., phenylpropanolamine, dextromethorphan, chlorpheniramine maleate, and paracetamol) by capillary zone electrophoresis and micellar electrokinetic chromatography. Factors affecting their separations were the buffer pH and the concentrations of buffer, surfactant and organic modifiers. Optimum results were obtained with a 10 mM sodium dihydrogen-phosphate-sodium tetraborate buffer containing 50 mM sodium dodecyl sulfate (SDS) and 5% methanol (MeOH), pH 9.0. The carrier electrolyte gave a baseline separation of phenylpropanolamine, dextromethorphan, chlorpheniramine maleate, and paracetamol with a resolution of 1.2, and the total migration time was 11.38 min.

  20. Interindividual and interethnic differences in the demethylation and glucuronidation of codeine.

    PubMed Central

    Yue, Q Y; Svensson, J O; Alm, C; Sjöqvist, F; Säwe, J

    1989-01-01

    1. The 8 h urinary excretion of codeine and seven of its metabolites was compared in 149 healthy Swedish Caucasians and 133 healthy Chinese following a single oral dose of 25 mg codeine phosphate. 2. The total 8 h urinary recovery of drug-related material was 74 +/- 24% in the Caucasians and 60 +/- 14% in the Chinese (P less than 0.001). The excretion of unchanged codeine was significantly higher in the Chinese (7.2%) compared with the Caucasians (4.3%, P less than 0.001). 3. The Caucasians excreted significantly greater proportions of codeine-6-glucuronide (C6G) (62%) than the Chinese (44%) (P less than 0.001). The frequency distribution of the log metabolic ratio (MR) for glucuronidation (codeine/C6G) was shifted towards higher values in the Chinese population. Males in both groups and Chinese smokers had significantly lower glucuronidation MRs than females and non-smokers in the respective populations (P less than 0.001). 4. The frequency distribution of the MR for O-demethylation (codeine/morphine (M) + M-3 and M-6-glucuronide (M3G and M6G) + normorphine (NM) was highly skewed in the Caucasians, suggestive of a bimodal distribution. There was a 160-fold interindividual variation in this MR. A unimodal distribution of the log O-demethylation MR was observed in Chinese. The Caucasians excreted less M and more M6G than did the Chinese (P less than 0.001). 5. Significantly more norcodeine (NC) and less NC-glucuronide (NCG) were excreted in the Chinese compared with the Caucasians (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2611085

  1. Study on the stereoselective excretion of tetrahydropalmatine enantiomers in rats and identification of in vivo metabolites by liquid chromatography-tandem mass spectrometry.

    PubMed

    Hong, Zhanying; Wen, Jun; Zhang, Quanlong; Fan, Guorong; Chai, Yifeng; Wu, Yutian

    2010-03-01

    The objective of this work was to study the stereoselectivity in excretion of tetrahydropalmatine (THP) enantiomers by rats and identify the metabolites of racemic THP (rac-THP) in rat urine. Urine and bile samples were collected at various time intervals after a single oral dose of rac-THP. The concentrations of THP enantiomers in rat urine and bile were determined using a modification of an achiral-chiral high-performance liquid chromatographic (HPLC) method that had been previously published. The cumulative urinary excretion over 96 h of (-)-THP and (+)-THP was found to be 55.49 +/- 36.9 microg and 18.33 +/- 9.7 microg, respectively. The cumulative biliary excretion over 24 h of (-)-THP and (+)-THP was 19.19 +/- 14.6 microg and 12.53 +/- 10.4 microg, respectively. The enantiomeric (-/+) concentration ratios of THP changed from 2.80 to 5.15 in urine, and from 1.36 to 1.80 in bile. The mean cumulative amount of (-)-THP was significantly higher than that of (+)-THP both in urine and bile samples. However, the enantiomeric (-/+) concentration ratios in rat urine and bile were significantly lower than those ratios in rat plasma. These findings suggested the excretion of THP enantiomers was stereoselective rather than a reflection of chiral pharmacokinetic aspects in plasma and (-)-THP was preferentially excreted in rat urine and bile. Three O-demethylation metabolites and the parent drug rac-THP were detected by liquid chromatography-tandem mass spectrometry in rat urine. One metabolite was obtained by preparative HPLC and identified as 10-O-demethyl-THP.

  2. Monitoring of kratom or Krypton intake in urine using GC-MS in clinical and forensic toxicology.

    PubMed

    Philipp, Anika A; Meyer, Markus R; Wissenbach, Dirk K; Weber, Armin A; Zoerntlein, Siegfried W; Zweipfenning, Peter G M; Maurer, Hans H

    2011-04-01

    The Thai medicinal plant Mitragyna speciosa (kratom) is misused as a herbal drug. Besides this, a new herbal blend has appeared on the drugs of abuse market, named Krypton, a mixture of O-demethyltramadol (ODT) and kratom. Therefore, urine drug screenings should include ODT and focus on the metabolites of the kratom alkaloids mitragynine (MG), paynantheine (PAY), speciogynine (SG), and speciociliatine (SC). The aim of this study was to develop a full-scan gas chromatography-mass spectrometry procedure for monitoring kratom or Krypton intake in urine after enzymatic cleavage of conjugates, solid-phase extraction, and trimethylsilylation. With use of reconstructed mass chromatography with the ions m/z 271, 286, 329, 344, 470, 526, 528, and 586, the presence of MG, 16-carboxy-MG, 9-O-demethyl-MG, and/or 9-O-demethyl-16-carboxy-MG could be indicated, and in case of Krypton, with m/z 58, 84, 116, 142, 303, 361, 393, and 451, the additional presence of ODT and its nor metabolite could be indicated. Compounds were identified by comparison with their respective reference spectra. Depending on the plant type, dose, administration route, and/or sampling time, further metabolites of MG, PAY, SG, and SC could be detected. The limits of detection (signal-to-noise ratio of 3) were 100 ng/ml for the parent alkaloids and 50 ng/ml for ODT. As mainly metabolites of the kratom alkaloids were detected in urine, the detectability of kratom was tested successfully using rat urine after administration of a common user's dose of MG. As the metabolism in humans was similar, this procedure should be suitable to prove an intake of kratom or Krypton.

  3. Cytochrome P450 CYP81A12 and CYP81A21 Are Associated with Resistance to Two Acetolactate Synthase Inhibitors in Echinochloa phyllopogon1[W

    PubMed Central

    Iwakami, Satoshi; Endo, Masaki; Saika, Hiroaki; Okuno, Junichi; Nakamura, Naoki; Yokoyama, Masao; Watanabe, Hiroaki; Toki, Seiichi; Uchino, Akira; Inamura, Tatsuya

    2014-01-01

    Previous studies have demonstrated multiple herbicide resistance in California populations of Echinochloa phyllopogon, a noxious weed in rice (Oryza sativa) fields. It was suggested that the resistance to two classes of acetolactate synthase-inhibiting herbicides, bensulfuron-methyl (BSM) and penoxsulam (PX), may be caused by enhanced activities of herbicide-metabolizing cytochrome P450. We investigated BSM metabolism in the resistant (R) and susceptible (S) lines of E. phyllopogon, which were originally collected from different areas in California. R plants metabolized BSM through O-demethylation more rapidly than S plants. Based on available information about BSM tolerance in rice, we isolated and analyzed P450 genes of the CYP81A subfamily in E. phyllopogon. Two genes, CYP81A12 and CYP81A21, were more actively transcribed in R plants compared with S plants. Transgenic Arabidopsis (Arabidopsis thaliana) expressing either of the two genes survived in media containing BSM or PX at levels at which the wild type stopped growing. Segregation of resistances in the F2 generation from crosses of R and S plants suggested that the resistance to BSM and PX were each under the control of a single regulatory element. In F6 recombinant inbred lines, BSM and PX resistances cosegregated with increased transcript levels of CYP81A12 and CYP81A21. Heterologously produced CYP81A12 and CYP81A21 proteins in yeast (Saccharomyces cerevisiae) metabolized BSM through O-demethylation. Our results suggest that overexpression of the two P450 genes confers resistance to two classes of acetolactate synthase inhibitors to E. phyllopogon. The overexpression of the two genes could be regulated simultaneously by a single trans-acting element in the R line of E. phyllopogon. PMID:24760819

  4. Identification of human hepatic cytochrome P450 enzymes involved in the metabolism of 8-prenylnaringenin and isoxanthohumol from hops (Humulus lupulus L.).

    PubMed

    Guo, Jian; Nikolic, Dejan; Chadwick, Lucas R; Pauli, Guido F; van Breemen, Richard B

    2006-07-01

    The female flowers of hops (Humulus lupulus L.) are used in the brewing of beer and are under investigation for use in dietary supplements for the management of menopausal symptoms in women. Hop extracts contain the weakly estrogenic compound isoxanthohumol (IX), proestrogenic xanthohumol, and the potent estrogen 8-prenylnaringenin (8PN). Because IX can be metabolized in the human liver to form 8PN, the specific cytochrome P450 (P450) enzymes responsible for this O-demethylation reaction were identified. In addition, the enzymes that convert IX and 8PN to their most abundant metabolites were identified because these metabolic pathways might also affect the estrogenicity of hop preparations. Specifically, the P450 enzymes that catalyze the oxidation of the prenyl side chains of IX and 8PN into trans- or cis-alcohols were investigated. Human liver microsomes and monoclonal antibodies that inhibit specific P450 enzymes were used in combination with liquid chromatography/mass spectrometry to identify the enzymes responsible for these transformations. CYP2C19 was found to catalyze the formation of both cis- and trans-alcohols of the prenyl side chain of 8PN with K(m) values of 14.8 +/- 3.2 and 16.6 +/- 4.6 microM, respectively. CYP2C8 converted 8PN regioselectively to the trans-alcohol of the prenyl group with a K(m) of 3.7 +/- 0.9 microM. Finally, CYP1A2 was found to catalyze the O-demethylation of IX to generate 8PN, with a K(m) value of 17.8 +/- 3.7 microM. These results suggest that the estrogenicity of hop constituents in vivo will depend in part on metabolic conversion that may show individual variation.

  5. Structure of aryl O -demethylase offers molecular insight into a catalytic tyrosine-dependent mechanism

    DOE PAGES

    Kohler, Amanda C.; Mills, Matthew J. L.; Adams, Paul D.; ...

    2017-04-03

    Some strains of soil and marine bacteria have evolved intricate metabolic pathways for using environmentally derived aromatics as a carbon source. Many of these metabolic pathways go through intermediates such as vanillate, 3-O-methylgallate, and syringate. Demethylation of these compounds is essential for downstream aryl modification, ring opening, and subsequent assimilation of these compounds into the tricarboxylic acid (TCA) cycle, and, correspondingly, there are a variety of associated aryl demethylase systems that vary in complexity. Intriguingly, only a basic understanding of the least complex system, the tetrahydrofolate-dependent aryl demethylase LigM from Sphingomonas paucimobilis, a bacterial strain that metabolizes lignin-derived aromatics, wasmore » previously available. LigM-catalyzed demethylation enables further modification and rin g opening of the single-ring aromatics vanillate and 3-Omethylgallate, which are common byproducts of biofuel production. We characterize aryl O-demethylation by LigM and report its 1.81-Å crystal structure, revealing a unique demethylase fold and a canonical folate-binding domain. Structural homology and geometry optimization calculations enabled the identification of LigM's tetrahydrofolate-binding site and protein-folate interactions. Computationally guided mutagenesis and kinetic analyses allowed the identification of the enzyme's aryl-binding site location and determination of its unique, catalytic tyrosine-dependent reaction mechanism. This work defines LigM as a distinct demethylase, both structurally and functionally, and provides insight into demethylation and its reaction requirements. Our results afford the mechanistic details required for efficient utilization of LigM as a tool for aryl O-demethylation and as a component of synthetic biology efforts to valorize previously underused aromatic compounds.« less

  6. Microbial and dietary factors associated with the 8-prenylnaringenin producer phenotype: a dietary intervention trial with fifty healthy post-menopausal Caucasian women.

    PubMed

    Bolca, Selin; Possemiers, Sam; Maervoet, Veerle; Huybrechts, Inge; Heyerick, Arne; Vervarcke, Stefaan; Depypere, Herman; De Keukeleire, Denis; Bracke, Marc; De Henauw, Stefaan; Verstraete, Willy; Van de Wiele, Tom

    2007-11-01

    Hop-derived food supplements and beers contain the prenylflavonoids xanthohumol (X), isoxanthohumol (IX) and the very potent phyto-oestrogen (plant-derived oestrogen mimic) 8-prenylnaringenin (8-PN). The weakly oestrogenic IX can be bioactivated via O-demethylation to 8-PN. Since IX usually predominates over 8-PN, human subjects may be exposed to increased doses of 8-PN. A dietary intervention trial with fifty healthy post-menopausal Caucasian women was undertaken. After a 4 d washout period, participants delivered faeces, blank urine and breath samples. Next, they started a 5 d treatment with hop-based supplements that were administered three times per d and on the last day, a 24 h urine sample was collected. A semi-quantitative FFQ was used to estimate fat, fibre, alcohol, caffeine and theobromine intakes. The recoveries of IX, 8-PN and X in the urine were low and considerable inter-individual variations were observed. A five-fold increase in the dosage of IX without change in 8-PN concentration resulted in a significant lower IX recovery and a higher 8-PN recovery. Classification of the subjects into poor (60%), moderate (25%) and strong (15%) 8-PN producers based on either urinary excretion or microbial bioactivation capacity gave comparable results. Recent antibiotic therapy seemed to affect the 8-PN production negatively. A positive trend between methane excretion and 8-PN production was observed. Strong 8-PN producers consumed less alcohol and had a higher theobromine intake. From this study we conclude that in vivo O-demethylation of IX increases the oestrogenic potency of hop-derived products.

  7. Corrinoid-Dependent Methyl Transfer Reactions Are Involved in Methanol and 3,4-Dimethoxybenzoate Metabolism by Sporomusa ovata.

    PubMed

    Stupperich, E; Konle, R

    1993-09-01

    Washed and air-oxidized proteins from Sporomusa ovata cleaved the C-O bond of methanol or methoxyaromatics and transferred the methyl to dl-tetrahydrofolate. The reactions strictly required a reductive activation by titanium citrate, catalytic amounts of ATP, and the addition of dl-tetrahydrofolate. Methylcorrinoid-containing proteins carried the methanol methyl, which was transferred to dl-tetrahydrofolate at a specific rate of 120 nmol h mg of protein. Tetrahydrofolate methylation diminished after the addition of 1-iodopropane or when the methyl donor methanol was replaced by 3,4-dimethoxybenzoate. However, whole Sporomusa cells utilize the methoxyl groups of 3,4-dimethoxybenzoate as a carbon source by a sequential O demethylation to 4-hydroxy-3-methoxybenzoate and 3,4-dihydroxybenzoate. The in vitro O demethylation of 3,4-[4-methoxyl-C]dimethoxybenzoate proceeded via two distinct corrinoid-containing proteins to form 5-[C]methyltetrahydrofolate at a specific rate of 200 nmol h mg of protein. Proteins from 3,4-dimethoxybenzoate-grown cells efficiently used methoxybenzoates with vicinal substituents only, but they were unable to activate methanol. These results emphasized that specific enzymes are involved in methanol activation as well as in the activation of various methoxybenzoates and that similar corrinoid-dependent methyl transfer pathways are employed in 5-methyl-tetrahydrofolate formation from these substrates. Methyl-tetrahydrofolate could be demethylated by a distinct methyl transferase. That enzyme activity was present in washed and air-oxidized cell extracts from methanol-grown cells and from 3,4-dimethoxybenzoate-grown cells. It used cob(I)alamin as the methyl acceptor in vitro, which was methylated at a rate of 48 nmol min mg of protein even when ATP was omitted from the assay mixture. This methyl-cob(III)alamin formation made possible a spectrophotometric quantification of the preceding methyl transfers from methanol or methoxybenzoates to dl-tetrahydrofolate.

  8. Identifying a Selective Substrate and Inhibitor Pair for the Evaluation of CYP2J2 Activity

    PubMed Central

    Lee, Caroline A.; Jones, J. P.; Katayama, Jonathan; Kaspera, Rüdiger; Jiang, Ying; Freiwald, Sascha; Smith, Evan; Walker, Gregory S.

    2012-01-01

    CYP2J2, an arachidonic acid epoxygenase, is recognized for its role in the first-pass metabolism of astemizole and ebastine. To fully assess the role of CYP2J2 in drug metabolism, a selective substrate and potent specific chemical inhibitor are essential. In this study, we report amiodarone 4-hydoxylation as a specific CYP2J2-catalyzed reaction with no CYP3A4, or other drug-metabolizing enzyme, involvement. Amiodarone 4-hydroxylation enabled the determination of liver relative activity factor and intersystem extrapolation factor for CYP2J2. Amiodarone 4-hydroxylation correlated with astemizole O-demethylation but not with CYP2J2 protein content in a sample of human liver microsomes. To identify a specific CYP2J2 inhibitor, 138 drugs were screened using terfenadine and astemizole as probe substrates with recombinant CYP2J2. Forty-two drugs inhibited CYP2J2 activity by ≥50% at 30 μM, but inhibition was substrate-dependent. Of these, danazol was a potent inhibitor of both hydroxylation of terfenadine (IC50 = 77 nM) and O-demethylation of astemizole (Ki = 20 nM), and inhibition was mostly competitive. Danazol inhibited CYP2C9, CYP2C8, and CYP2D6 with IC50 values of 1.44, 1.95, and 2.74 μM, respectively. Amiodarone or astemizole were included in a seven-probe cocktail for cytochrome P450 (P450) drug-interaction screening potential, and astemizole demonstrated a better profile because it did not appreciably interact with other P450 probes. Thus, danazol, amiodarone, and astemizole will facilitate the ability to determine the metabolic role of CYP2J2 in hepatic and extrahepatic tissues. PMID:22328583

  9. Identifying a selective substrate and inhibitor pair for the evaluation of CYP2J2 activity.

    PubMed

    Lee, Caroline A; Jones, J P; Katayama, Jonathan; Kaspera, Rüdiger; Jiang, Ying; Freiwald, Sascha; Smith, Evan; Walker, Gregory S; Totah, Rheem A

    2012-05-01

    CYP2J2, an arachidonic acid epoxygenase, is recognized for its role in the first-pass metabolism of astemizole and ebastine. To fully assess the role of CYP2J2 in drug metabolism, a selective substrate and potent specific chemical inhibitor are essential. In this study, we report amiodarone 4-hydoxylation as a specific CYP2J2-catalyzed reaction with no CYP3A4, or other drug-metabolizing enzyme, involvement. Amiodarone 4-hydroxylation enabled the determination of liver relative activity factor and intersystem extrapolation factor for CYP2J2. Amiodarone 4-hydroxylation correlated with astemizole O-demethylation but not with CYP2J2 protein content in a sample of human liver microsomes. To identify a specific CYP2J2 inhibitor, 138 drugs were screened using terfenadine and astemizole as probe substrates with recombinant CYP2J2. Forty-two drugs inhibited CYP2J2 activity by ≥50% at 30 μM, but inhibition was substrate-dependent. Of these, danazol was a potent inhibitor of both hydroxylation of terfenadine (IC(50) = 77 nM) and O-demethylation of astemizole (K(i) = 20 nM), and inhibition was mostly competitive. Danazol inhibited CYP2C9, CYP2C8, and CYP2D6 with IC(50) values of 1.44, 1.95, and 2.74 μM, respectively. Amiodarone or astemizole were included in a seven-probe cocktail for cytochrome P450 (P450) drug-interaction screening potential, and astemizole demonstrated a better profile because it did not appreciably interact with other P450 probes. Thus, danazol, amiodarone, and astemizole will facilitate the ability to determine the metabolic role of CYP2J2 in hepatic and extrahepatic tissues.

  10. Metabolism and disposition of N,N-dimethyltryptamine and harmala alkaloids after oral administration of ayahuasca.

    PubMed

    Riba, Jordi; McIlhenny, Ethan H; Valle, Marta; Bouso, José Carlos; Barker, Steven A

    2012-01-01

    Ayahuasca is an Amazonian psychotropic plant tea obtained from Banisteriopsis caapi, which contains β-carboline alkaloids, chiefly harmine, harmaline and tetrahydroharmine. The tea usually incorporates the leaves of Psychotria viridis or Diplopterys cabrerana, which are rich in N,N-dimethyltryptamine (DMT), a psychedelic 5-HT(2A/1A/2C) agonist. The β-carbolines reversibly inhibit monoamine-oxidase (MAO), effectively preventing oxidative deamination of the orally labile DMT and allowing its absorption and access to the central nervous system. Despite increased use of the tea worldwide, the metabolism and excretion of DMT and the β-carbolines has not been studied systematically in humans following ingestion of ayahuasca. In the present work, we used an analytical method involving high performance liquid chromatography (HPLC)/electrospray ionization (ESI)/selected reaction monitoring (SRM)/tandem mass spectrometry(MS/MS) to characterize the metabolism and disposition of ayahuasca alkaloids in humans. Twenty-four-hour urine samples were obtained from 10 healthy male volunteers following administration of an oral dose of encapsulated freeze-dried ayahuasca (1.0 mg DMT/kg body weight). Results showed that less than 1% of the administered DMT dose was excreted unchanged. Around 50% was recovered as indole-3-acetic acid but also as DMT-N-oxide (10%) and other MAO-independent compounds. Recovery of DMT plus metabolites reached 68%. Harmol, harmalol, and tetrahydroharmol conjugates were abundant in urine. However, recoveries of each harmala alkaloid plus its O-demethylated metabolite varied greatly between 9 and 65%. The present results show the existence in humans of alternative metabolic routes for DMT other than biotransformation by MAO. Also that O-demethylation plus conjugation is an important but probably not the only metabolic route for the harmala alkaloids in humans.

  11. The pathogenetic role of adulterants in 5 cases of drug addicts with a fatal outcome.

    PubMed

    Barbera, Nunziata; Busardò, Francesco Paolo; Indorato, Francesca; Romano, Guido

    2013-04-10

    The purpose of the present study is to determine the role of lidocaine, caffeine and dextromethorphan, used as adulterant substances, in five cases of drug overdose which have come to our attention. Taking into account the pharmacological mechanism, blood concentration and route of administration (intravenous) we evaluated the hypothesis that these substances could act with a synergistic effect - or at least additive - with the illicit drugs on the central nervous system and cardiovascular system.

  12. Do OTC remedies relieve cough in acute URIs?

    PubMed

    Dealleaume, Lauren; Tweed, Beth; Neher, Jon O

    2009-10-01

    Dextromethorphan (DM) for adults and honey for children provide some relief. DM may modestly decrease cough in adults compared with placebo. The data supporting zinc for the common cold are mixed. Antihistamines, antihistamine-decongestant combinations, and guaifenesin do not provide greater relief than placebo in adults. In children, antihistamines, decongestants, DM, or combinations of them do not relieve cough better than placebo. Honey may modestly decrease frequency and severity of cough compared with DM or no treatment.

  13. Toxicity and use of over-the-counter cough and cold medication in the pediatric population.

    PubMed

    Montgomery, Emily J; Wasserman, Gary S

    2008-01-01

    Discussions of the efficacy and toxicity of over-the-counter cough and cold medication have been circulating in the pediatric literature for years. Adverse effects of these medications and the lack of evidence of their efficacy in children make their use a serious matter. An additional consideration for physicians is the recreational use of over-the-counter medications, including adolescent abuse of dextromethorphan. The recent increase in media attention to these issues warrants further review.

  14. Population pharmacokinetic modelling to assess the impact of CYP2D6 and CYP3A metabolic phenotypes on the pharmacokinetics of tamoxifen and endoxifen

    PubMed Central

    ter Heine, Rob; Binkhorst, Lisette; de Graan, Anne Joy M; de Bruijn, Peter; Beijnen, Jos H; Mathijssen, Ron H J; Huitema, Alwin D R

    2014-01-01

    Aims Tamoxifen is considered a pro-drug of its active metabolite endoxifen. The major metabolic enzymes involved in endoxifen formation are CYP2D6 and CYP3A. There is considerable evidence that variability in activity of these enzymes influences endoxifen exposure and thereby may influence the clinical outcome of tamoxifen treatment. We aimed to quantify the impact of metabolic phenotype on the pharmacokinetics of tamoxifen and endoxifen. Methods We assessed the CYP2D6 and CYP3A metabolic phenotypes in 40 breast cancer patients on tamoxifen treatment with a single dose of dextromethorphan as a dual phenotypic probe for CYP2D6 and CYP3A. The pharmacokinetics of dextromethorphan, tamoxifen and their relevant metabolites were analyzed using non-linear mixed effects modelling. Results Population pharmacokinetic models were developed for dextromethorphan, tamoxifen and their metabolites. In the final model for tamoxifen, the dextromethorphan derived metabolic phenotypes for CYP2D6 as well as CYP3A significantly (P < 0.0001) explained 54% of the observed variability in endoxifen formation (inter-individual variability reduced from 55% to 25%). Conclusions We have shown that not only CYP2D6, but also CYP3A enzyme activity influences the tamoxifen to endoxifen conversion in breast cancer patients. Our developed model may be used to assess separately the impact of CYP2D6 and CYP3A mediated drug–drug interactions with tamoxifen without the necessity of administering this anti-oestrogenic drug and to support Bayesian guided therapeutic drug monitoring of tamoxifen in routine clinical practice. PMID:24697814

  15. Biochemical Markers of Brain Injury: An Integrated Proteomics-Based Approach

    DTIC Science & Technology

    2011-12-01

    pharmacological therapy was evaluated. BODY: The specific aims, overall, were not altered. SOW 1: will employ global, high throughput proteomic and...levels to track the effects of Dextromethorphan therapy and correlation to histopathology and neurological outcome. 6 First we tested whether...drug therapies for PBBI. All these experiments were all done with one injury magnitude (10% PBBI). First we tested a derivative of glycine-proline

  16. Crystal structures of bis­[(9S,13S,14S)-3-meth­oxy-17-methyl­morphinanium] tetra­chlorido­cobaltate and tetra­chlorido­cuprate

    PubMed Central

    Gauchat, Eric; Nazarenko, Alexander Y.

    2017-01-01

    (9S,13S,14S)-3-Meth­oxy-17-methyl­morphinan (dextromethorphan) forms two isostructural salts with (a) tetra­chlorido­cobaltate, namely bis­[(9S,13S,14S)-3-meth­oxy-17-methyl­morphinanium] tetra­chlorido­cobaltate, (C18H26NO)2[CoCl4], and (b) tetra­chlorido­cuprate, namely bis­[(9S,13S,14S)-3-meth­oxy-17-methyl­morphinanium] tetra­chlorido­cuprate, (C18H26NO)2[CuCl4]. The distorted tetra­hedral anions are located on twofold rotational axes. The dextromethorphan cation can be described as being composed of two ring systems, a tetra­hydro­naphthalene system A+B and a deca­hydro­isoquinolinium subunit C+D, that are nearly perpendicular to one another: the angle between mean planes of the A+B and C+D moieties is 78.8 (1)° for (a) and 79.0 (1)° for (b). Two symmetry-related cations of protonated dextromethorphan are connected to the tetra­chlorido­cobaltate (or tetra­chlorido­cuprate) anions via strong N—H⋯Cl hydrogen bonds, forming neutral ion associates. These associates are packed in the (001) plane with no strong attractive bonding between them. Both compounds are attractive crystalline forms for unambiguous identification of the dextromethorphan and, presumably, of its optical isomer, levomethorphan. PMID:28083138

  17. Laser electrospray mass spectrometry of adsorbed molecules at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Brady, John J.; Judge, Elizabeth J.; Simon, Kuriakose; Levis, Robert J.

    2010-02-01

    Atmospheric pressure mass analysis of solid phase biomolecules is performed using laser electrospray mass spectrometry (LEMS). A non-resonant femtosecond duration laser pulse vaporizes native samples at atmospheric pressure for subsequent electrospray ionization and transfer into a mass spectrometer. LEMS was used to detect a complex molecule (irinotecan HCl), a complex mixture (cold medicine formulation with active ingredients: acetaminophen, dextromethorphan HBr and doxylamine succinate), and a biological building block (deoxyguanosine) deposited on steel surfaces without a matrix molecule.

  18. Central inhibition of initiation of swallowing by systemic administration of diazepam and baclofen in anaesthetized rats.

    PubMed

    Tsujimura, Takanori; Sakai, Shogo; Suzuki, Taku; Ujihara, Izumi; Tsuji, Kojun; Magara, Jin; Canning, Brendan J; Inoue, Makoto

    2017-05-01

    Dysphagia is caused not only by neurological and/or structural damage but also by medication. We hypothesized memantine, dextromethorphan, diazepam, and baclofen, all commonly used drugs with central sites of action, may regulate swallowing function. Swallows were evoked by upper airway (UA)/pharyngeal distension, punctate mechanical stimulation using a von Frey filament, capsaicin or distilled water (DW) applied topically to the vocal folds, and electrical stimulation of a superior laryngeal nerve (SLN) in anesthetized rats and were documented by recording electromyographic activation of the suprahyoid and thyrohyoid muscles and by visualizing laryngeal elevation. The effects of intraperitoneal or topical administration of each drug on swallowing function were studied. Systemic administration of diazepam and baclofen, but not memantine or dextromethorphan, inhibited swallowing evoked by mechanical, chemical, and electrical stimulation. Both benzodiazepines and GABAA receptor antagonists diminished the inhibitory effects of diazepam, whereas a GABAB receptor antagonist diminished the effects of baclofen. Topically applied diazepam or baclofen had no effect on swallowing. These data indicate that diazepam and baclofen act centrally to inhibit swallowing in anesthetized rats.NEW & NOTEWORTHY Systemic administration of diazepam and baclofen, but not memantine or dextromethorphan, inhibited swallowing evoked by mechanical, chemical, and electrical stimulation. Both benzodiazepines and GABAA receptor antagonists diminished the inhibitory effects of diazepam, whereas a GABAB receptor antagonist diminished the effects of baclofen. Topical applied diazepam or baclofen was without effect on swallowing. Diazepam and baclofen act centrally to inhibit swallowing in anesthetized rats. Copyright © 2017 the American Physiological Society.

  19. AVP-786 for the treatment of agitation in dementia of the Alzheimer's type.

    PubMed

    Garay, Ricardo P; Grossberg, George T

    2017-01-01

    Agitation is common and distressing in patients with Alzheimer-type dementia, but safe, effective treatments remain elusive. Psychological treatments are first-line options, but they have limited efficacy. Off-label psychotropic medications are frequently used, but they also have limited effectiveness, and their use may have harmful side effects, including death. Areas covered: This review discusses the history leading to the conception of AVP-786 (deuterated (d6)-dextromethorphan/quinidine), its pharmacokinetic and pharmacodynamic profiles and safety issues, together with an overview of recent clinical trials. Data were found in the medical literature, in US and EU clinical trial registries and in information provided by the manufacturer. Expert opinion: AVP-786 is one of six investigational compounds in recent phase III clinical development for agitation in Alzheimer disease (AD). Quinidine and deuteration appear to prolong dextromethorphan's plasma half-life and facilitate brain penetration. The FDA granted fast-track designation to AVP-786 and allowed use of data generated on dextromethorphan-quinidine (AVP-923, Nuedexta®) for regulatory filings. AVP-923 reduced agitation in AD and was well tolerated in a phase II RCT that included more than 200 patients. A phase III clinical development program of AVP-786 for AD agitation was recently initiated. This program is expected to start generating results in July 2018.

  20. Activities of cytochrome P450 1A2, N-acetyltransferase 2, xanthine oxidase, and cytochrome P450 2D6 are unaltered in children with cystic fibrosis.

    PubMed

    Kennedy, Mary Jayne; Scripture, Charity D; Kashuba, Angela D M; Scott, Christy S; Gaedigk, Andrea; Kearns, Gregory L

    2004-03-01

    The activities of hepatic cytochrome P450 (CYP) 1A2, N-acetyltransferase 2 (NAT-2), xanthine oxidase (XO), and CYP2D6 were evaluated in 12 young children (aged 3-8 years) with mild cystic fibrosis (CF) and 12 age-matched healthy control subjects by use of standard caffeine and dextromethorphan phenotyping methods. Subjects were given 4 oz of Coca-Cola (approximately 35 mg caffeine) (The Coca-Cola Company, Atlanta, Ga) and a single 0.5-mg/kg dose of dextromethorphan. Urine was collected for 8 hours after biomarker administration, and enzyme activity was assessed by use of previously validated caffeine and dextromethorphan molar ratios. CYP2D6 genotyping was also performed in 10 of 12 subjects with CF and 11 of 12 control subjects. There were no significant differences in the urinary molar ratios for any of the enzyme systems evaluated. These data suggest that CF does not alter the activities of CYP1A2, NAT-2, XO, and CYP2D6. Altered biotransformation of drugs in this patient population is likely enzyme- and isoform-specific and thus is apparent for only selected compounds that are substrates for enzymes other than CYP1A2, NAT-2, XO, and CYP2D6.

  1. Clinical inhibition of CYP2D6-catalysed metabolism by the antianginal agent perhexiline

    PubMed Central

    Davies, Benjamin J L; Coller, Janet K; James, Heather M; Gillis, David; Somogyi, Andrew A; Horowitz, John D; Morris, Raymond G; Sallustio, Benedetta C

    2004-01-01

    Aims Perhexiline is an antianginal agent that displays both saturable and polymorphic metabolism via CYP2D6. The aim of this study was to determine whether perhexiline produces clinically significant inhibition of CYP2D6-catalysed metabolism in angina patients. Methods The effects of perhexiline on CYP2D6-catalysed metabolism were investigated by comparing urinary total dextrorphan/dextromethorphan metabolic ratios following a single dose of dextromethorphan (16.4 mg) in eight matched control patients not taking perhexiline and 24 patients taking perhexiline. All of the patients taking perhexiline had blood drawn for CYP2D6 genotyping as well as to measure plasma perhexiline and cis-OH-perhexiline concentrations. Results Median (range) dextrorphan/dextromethorphan metabolic ratios were significantly higher (P < 0.0001) in control patients, 271.1 (40.3–686.1), compared with perhexiline-treated patients, 5.0 (0.3–107.9). In the perhexiline-treated group 10/24 patients had metabolic ratios consistent with poor metabolizer phenotypes; however, none was a genotypic poor metabolizer. Interestingly, 89% of patients who had phenocopied to poor metabolizers had only one functional CYP2D6 gene. There was a significant negative linear correlation between the log of the dextrorphan/dextromethorphan metabolic ratio and plasma perhexiline concentrations (r2 = 0.69, P < 0.0001). Compared with patients with at least two functional CYP2D6 genes, those with one functional gene were on similar perhexiline dosage regimens but had significantly higher plasma perhexiline concentrations, 0.73 (0.21–1.00) vs. 0.36 (0.04–0.69) mg l−1 (P = 0.04), lower cis-OH-perhexiline/perhexiline ratios, 2.85 (0.35–6.10) vs. 6.51 (1.84–11.67) (P = 0.03), and lower dextrorphan/dextromethorphan metabolic ratios, 2.51 (0.33–39.56) vs. 11.80 (2.90–36.93) (P = 0.005). Conclusions Perhexiline significantly inhibits CYP2D6-catalysed metabolism in angina patients. The plasma cis

  2. Altered expression of small heterodimer partner governs cytochrome P450 (CYP) 2D6 induction during pregnancy in CYP2D6-humanized mice.

    PubMed

    Koh, Kwi Hye; Pan, Xian; Shen, Hong-Wu; Arnold, Samuel L M; Yu, Ai-Ming; Gonzalez, Frank J; Isoherranen, Nina; Jeong, Hyunyoung

    2014-02-07

    Substrates of a major drug-metabolizing enzyme CYP2D6 display increased elimination during pregnancy, but the underlying mechanisms are unknown in part due to a lack of experimental models. Here, we introduce CYP2D6-humanized (Tg-CYP2D6) mice as an animal model where hepatic CYP2D6 expression is increased during pregnancy. In the mouse livers, expression of a known positive regulator of CYP2D6, hepatocyte nuclear factor 4α (HNF4α), did not change during pregnancy. However, HNF4α recruitment to CYP2D6 promoter increased at term pregnancy, accompanied by repressed expression of small heterodimer partner (SHP). In HepG2 cells, SHP repressed HNF4α transactivation of CYP2D6 promoter. In transgenic (Tg)-CYP2D6 mice, SHP knockdown led to a significant increase in CYP2D6 expression. Retinoic acid, an endogenous compound that induces SHP, exhibited decreased hepatic levels during pregnancy in Tg-CYP2D6 mice. Administration of all-trans-retinoic acid led to a significant decrease in the expression and activity of hepatic CYP2D6 in Tg-CYP2D6 mice. This study provides key insights into mechanisms underlying altered CYP2D6-mediated drug metabolism during pregnancy, laying a foundation for improved drug therapy in pregnant women.

  3. The design and development of fesoterodine as a prodrug of 5-hydroxymethyl tolterodine (5-HMT), the active metabolite of tolterodine.

    PubMed

    Malhotra, B; Gandelman, K; Sachse, R; Wood, N; Michel, M C

    2009-01-01

    This review highlights the design and development of fesoterodine (Toviaz) as a prodrug of 5-hydroxymethyl tolterodine (5-HMT), which is also the active metabolite of tolterodine, for the treatment of overactive bladder (OAB). Tolterodine and 5-HMT are both potent antimuscarinic agents. A prodrug approach was necessary for systemic bioavailability of 5-HMT after oral administration. Fesoterodine was selected amongst a series of ester analogues of 5-HMT to develop an advanced OAB treatment with an optimum biopharmaceutics profile, while maintaining a pharmacological link to tolterodine. While tolterodine and 5-HMT have similar antimuscarinic activity, the logD value, a determinant of lipophilicity and permeability across biological interfaces such as the gut wall and blood-brain barrier, is considerably lower for 5-HMT (0.74) versus tolterodine (1.83). In contrast to the cytochrome P450 (CYP) 2D6-mediated metabolism of tolterodine, 5-HMT formation from fesoterodine occurs via ubiquitous nonspecific esterases. Consequently, treatment with fesoterodine results in consistent, genotype-independent exposure to a singular active moiety (5-HMT); treatment with tolterodine results in CYP2D6 genotype-dependent exposure to varying proportions of two active moieties (5-HMT and tolterodine). At least partially due to the avoidance of variations in pharmacokinetic exposures observed with tolterodine, it was possible to develop fesoterodine with the flexibility of two efficacious and well-tolerated dosage regimens of 4 and 8 mg daily.

  4. Metabolism of MPTP by cytochrome P4502D6 and the demonstration of 2D6 mRNA in human foetal and adult brain by in situ hybridization.

    PubMed

    Gilham, D E; Cairns, W; Paine, M J; Modi, S; Poulsom, R; Roberts, G C; Wolf, C R

    1997-01-01

    1. 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a thermal breakdown product of synthetic 'street' heroin, is known to cause Parkinson's Disease-like symptoms in man. 2. The mechanism of action of this neurotoxin is thought to involve activation by the monoamine oxidase B system and subsequent toxicity by inhibition of neuronal mitochondrial respiration. The manifestation of toxicity will be a balance between the rate of activation of this compound versus its rate of inactivation through metabolism by enzymes such as the cytochrome P450-dependent monooxygenases. 3. In this report we demonstrate that MPTP N-demethylation, a detoxification pathway, is catalysed by cytochrome P450 CYP2D6 and up to 40% of the hepatic metabolism is mediated by this enzyme. 4. Perhaps more importantly we also demonstrate by in situ hybridization that CYP2D6 is localized in the pigmented neurons of the substantia nigra indicating that 2D6-mediated detoxification will occur in target cells. 5. These data present evidence that CYP2D6 will be a factor in susceptibility to MPTP neuronal toxicity and provide a biochemical rationale for the genetic observations linking a polymorphism at the CYP2D6 locus with susceptibility to Parkinson's.

  5. Effect of dronedarone on the pharmacokinetics of carvedilol following oral administration to rats.

    PubMed

    Kim, Min-Soo; Baek, In-Hwan

    2017-09-20

    Dronedarone is a CYP2D6 inhibitor; therefore, it is prudent to exercise caution when concurrently administering CYP2D6-metabolized β-blockers because of a lack of published data on potential drug interactions. The aim of this study was to investigate the effect of dronedarone on the pharmacokinetics of orally administered carvedilol in rats. Twenty male Sprague-Dawley rats were randomly divided into two groups and 10mg/kg carvedilol was administered to the rat with or without dronedarone pretreatment in a parallel design. Blood samples were collected before and after 0.25, 0.5, 0.75, 1, 2, 4, 6, 8, 12, and 24h of drug administration. The plasma concentration of carvedilol was determined using LC-MS/MS. The systemic exposure to carvedilol was significantly increased and elimination of carvedilol was significantly decreased in the dronedarone-pretreated rats than in the vehicle-pretreated rats. The one-compartment model with first-order absorption and elimination was sufficient to explain the pharmacokinetic characters after single oral administration of carvedilol to both vehicle-pretreated and dronedarone-pretreated rats. This study suggests that dronedarone inhibits CYP2D6-mediated carvedilol metabolism, and dose adjustment is needed in carvedilol and dronedarone combination therapy. Further studies are needed to clarify the effect of dronedarone on carvedilol and CYP2D6 substrates in clinical use. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Effect of a New Prokinetic Agent DA-9701 Formulated with Corydalis Tuber and Pharbitidis Semen on Cytochrome P450 and UDP-Glucuronosyltransferase Enzyme Activities in Human Liver Microsomes

    PubMed Central

    Ji, Hye Young; Liu, Kwang Hyeon; Jeong, Ji Hyeon; Lee, Dae-Young; Shim, Hyun Joo; Son, Miwon; Lee, Hye Suk

    2012-01-01

    DA-9701 is a new botanical drug composed of the extracts of Corydalis tuber and Pharbitidis semen, and it is used as an oral therapy for the treatment of functional dyspepsia in Korea. The inhibitory potentials of DA-9701 and its component herbs, Corydalis tuber and Pharbitidis semen, on the activities of seven major human cytochrome P450 (CYP) enzymes and four UDP-glucuronosyltransferase (UGT) enzymes in human liver microsomes were investigated using liquid chromatography-tandem mass spectrometry. DA-9701 and Corydalis tuber extract slightly inhibited UGT1A1-mediated etoposide glucuronidation, with 50% inhibitory concentration (IC50) values of 188 and 290 μg/mL, respectively. DA-9701 inhibited CYP2D6-catalyzed bufuralol 1′-hydroxylation with an inhibition constant (Ki) value of 6.3 μg/mL in a noncompetitive manner. Corydalis tuber extract competitively inhibited CYP2D6-mediated bufuralol 1′-hydroxylation, with a Ki value of 3.7 μg/mL, whereas Pharbitidis semen extract showed no inhibition. The volume in which the dose could be diluted to generate an IC50 equivalent concentration (volume per dose index) value of DA-9701 for inhibition of CYP2D6 activity was 1.16 L/dose, indicating that DA-9701 may not be a potent CYP2D6 inhibitor. Further clinical studies are warranted to evaluate the in vivo extent of the observed in vitro interactions. PMID:22548118

  7. Effect of penicillin-based antibiotics, amoxicillin, ampicillin, and piperacillin, on drug-metabolizing activities of human hepatic cytochromes P450.

    PubMed

    Niwa, Toshiro; Morimoto, Mari; Hirai, Takako; Hata, Tomomi; Hayashi, Misato; Imagawa, Yurie

    2016-02-01

    The effects of three kinds of penicillin-based antibiotics, amoxicillin, ampicillin, and piperacillin, on drug-metabolizing activity of human hepatic cytochrome P450 (P450 or CYP) were investigated. Metabolic activities of P450s expressed in recombinant Escherichia coli at substrate concentrations around the Michaelis constant were compared in the presence or absence of the antibiotics. Amoxicillin, ampicillin, and piperacillin at 0.5 or 1 mM concentrations neither inhibited nor stimulated CYP2C9-mediated tolbutamide methylhydroxylation, CYP2D6-mediated dopamine formation from p-tyramine, or CYP3A4- or CYP3A5-mediated testosterone 6β-hydroxylation. However, amoxicillin and piperacillin inhibited CYP2C8-mediated aminopyrine N-demethylation at 50% inhibitory concentration of 0.83 and 1.14 mM, respectively. These results suggest that piperacillin might inhibit CYP2C8 clinically, although the interactions between these three penicillin-based antibiotics and other drugs that are metabolized by P450s investigated would not be clinically significant.

  8. Systematic and quantitative assessment of the effect of chronic kidney disease on CYP2D6 and CYP3A4/5.

    PubMed

    Yoshida, K; Sun, B; Zhang, L; Zhao, P; Abernethy, D R; Nolin, T D; Rostami-Hodjegan, A; Zineh, I; Huang, S-M

    2016-07-01

    Recent reviews suggest that chronic kidney disease (CKD) can affect the pharmacokinetics of nonrenally eliminated drugs, but the impact of CKD on individual elimination pathways has not been systematically evaluated. In this study we developed a comprehensive dataset of the effect of CKD on the pharmacokinetics of CYP2D6- and CYP3A4/5-metabolized drugs. Drugs for evaluation were selected based on clinical drug-drug interaction (CYP3A4/5 and CYP2D6) and pharmacogenetic (CYP2D6) studies. Information from dedicated CKD studies was available for 13 and 18 of the CYP2D6 and CYP3A4/5 model drugs, respectively. Analysis of these data suggested that CYP2D6-mediated clearance is generally decreased in parallel with the severity of CKD. There was no apparent relationship between the severity of CKD and CYP3A4/5-mediated clearance. The observed elimination-route dependency in CKD effects between CYP2D6 and CYP3A4/5 may inform the need to conduct clinical CKD studies with nonrenally eliminated drugs for optimal use of drugs in patients with CKD. © 2015, The American Society for Clinical Pharmacology and Therapeutics.

  9. Activity levels of tamoxifen metabolites at the estrogen receptor and the impact of genetic polymorphisms of phase I and II enzymes on their concentration levels in plasma.

    PubMed

    Mürdter, T E; Schroth, W; Bacchus-Gerybadze, L; Winter, S; Heinkele, G; Simon, W; Fasching, P A; Fehm, T; Eichelbaum, M; Schwab, M; Brauch, H

    2011-05-01

    The therapeutic effect of tamoxifen depends on active metabolites, e.g., cytochrome P450 2D6 (CYP2D6) mediated formation of endoxifen. To test for additional relationships, 236 breast cancer patients were genotyped for CYP2D6, CYP2C9, CYP2B6, CYP2C19, CYP3A5, UGT1A4, UGT2B7, and UGT2B15; also, plasma concentrations of tamoxifen and 22 of its metabolites, including the (E)-, (Z)-, 3-, and 4'-hydroxymetabolites as well as their glucuronides, were quantified using liquid chromatography-tandem mass spectrometry (MS). The activity levels of the metabolites were measured using an estrogen response element reporter assay; the strongest estrogen receptor inhibition was found for (Z)-endoxifen and (Z)-4-hydroxytamoxifen (inhibitory concentration 50 (IC50) 3 and 7 nmol/l, respectively). CYP2D6 genotypes explained 39 and 9% of the variability of steady-state concentrations of (Z)-endoxifen and (Z)-4-hydroxytamoxifen, respectively. Among the poor metabolizers, 93% had (Z)-endoxifen levels below IC90 values, underscoring the role of CYP2D6 deficiency in compromised tamoxifen bioactivation. For other enzymes tested, carriers of reduced-function CYP2C9 (*2, *3) alleles had lower plasma concentrations of active metabolites (P < 0.004), pointing to the role of additional pathways.

  10. Inhibition of cough reflex sensitivity by diphenhydramine during acute viral respiratory tract infection.

    PubMed

    Dicpinigaitis, Peter V; Dhar, Sean; Johnson, Amber; Gayle, Yvonne; Brew, John; Caparros-Wanderley, Wilson

    2015-06-01

    Currently available over-the-counter cough remedies historically have been criticized for lack of scientific evidence supporting their efficacy. Although the first-generation antihistamine diphenhydramine is classified as an antitussive by the United States Food and Drug Administration, to the authors' knowledge it has never been shown to inhibit cough reflex sensitivity in subjects with pathological cough. To evaluate the effect of diphenhydramine on cough reflex sensitivity. Montefiore Medical Center, an academic medical center in New York City. Twenty two subjects with acute viral upper respiratory tract infection (common cold) underwent cough reflex sensitivity measurement employing capsaicin challenge on 3 separate days, 2 h after ingesting single doses of study drug (to coincide with peak blood concentrations), administered in randomized, double-blind manner: a multicomponent syrup containing diphenhydramine (25 mg), phenylephrine (10 mg), in a natural cocoa formulation; dextromethorphan (30 mg) syrup; and, placebo syrup. The standard endpoint of cough challenge was used: concentration of capsaicin inducing ≥5 coughs (C5). Effect on cough reflex sensitivity (C5). A significant difference (p = 0.0024) was established among groups, with pairwise analysis revealing a significant increase in mean log C5 (0.4 ± 0.55 (SD); p < 0.01) for the diphenhydramine-containing medication versus placebo, but not for dextromethorphan versus placebo. Our results provide the initial evidence of the ability of diphenhydramine to inhibit cough reflex sensitivity in subjects with acute pathological cough. Timing of cough reflex sensitivity measurement may not have allowed demonstration of maximal antitussive effect of dextromethorphan.

  11. Crying and suicidal, but not depressed. Pseudobulbar affect in multiple sclerosis successfully treated with valproic acid: Case report and literature review.

    PubMed

    Johnson, Bridgette; Nichols, Scott

    2015-12-01

    Pseudobulbar affect/emotional incontinence is a potentially disabling condition characterized by expressions of affect or emotions out of context from the normal emotional basis for those expressions. This condition can result in diagnostic confusion and unrelieved suffering when clinicians interpret the emotional expressions at face value. In addition, the nomenclature, etiology, and treatment for this condition remain unclear in the medical literature. We report the case of a 60-year-old woman with multiple sclerosis who was referred to an inpatient psychiatry unit with complaints of worsening depression along with hopelessness, characterized by unrelenting crying. Our investigation showed that her symptoms were caused by pseudobulbar affect/emotional incontinence stemming from multiple sclerosis. The patient's history of multiple sclerosis and the fact that she identified herself as depressed only because of her incessant crying suggested that her symptoms might be due to the multiple sclerosis rather than to a depressive disorder. Magnetic resonance imaging demonstrated a new plaque consistent with multiple sclerosis lateral to her corpus callosum. Her symptoms resolved completely within three days on valproic acid but returned after she was cross-tapered to dextromethorphan plus quinidine, which is the FDA-approved treatment for this condition. This case provides important additional information to the current literature on pseudobulbar affect/emotional incontinence. The existing literature suggests a selective serotonin reuptake inhibitor (SSRI) and dextromethorphan/quinidine (Nuedexta) as first-line treatments; however, our patient was taking an SSRI at the time of presentation without appreciable benefit, and her symptoms responded to valproic acid but not to the dextromethorphan/quinidine. In addition, the case and the literature review suggest that the current nomenclature for this constellation of symptoms can be misleading.

  12. A Systematic Review of NMDA Receptor Antagonists for Treatment of Neuropathic Pain in Clinical Practice.

    PubMed

    Aiyer, Rohit; Mehta, Neel; Gungor, Semih; Gulati, Amitabh

    2017-09-01

    To investigate the efficacy of N-methyl-D-aspartate receptor (NMDA) receptor antagonists for neuropathic pain and review literature to determine if specific pharmacologic agents provide adequate neuropathic pain relief. Literature was reviewed on PubMed using a variety of key words for 8 NMDA receptor antagonists. These key words include: "Ketamine and Neuropathy", "Ketamine and Neuropathic Pain", "Methadone and Neuropathy", "Methadone and Neuropathic Pain", "Memantine and Neuropathic pain", "Memantine and Neuropathy", "Amantadine and Neuropathic Pain", "Amantadine and Neuropathy", "Dextromethorphan and Neuropathic Pain", "Dextromethorphan and Neuropathy", "Carbamazepine and Neuropathic Pain", "Carbamazepine and Neuropathy", "Valproic Acid and Neuropathy", "Valproic Acid and Neuropathic Pain", "Phenytoin and Neuropathy" and "Phenytoin and Neuropathic Pain". With the results, the papers were reviewed using the PRISMA (Preferred Reporting in Systematic and Meta-Analyses) guideline. A total of 58 randomized controlled trials were reviewed among 8 pharmacologic agents, which are organized by date and alphabetical order. Of the trials for ketamine, 15 showed some benefit for analgesia. Methadone had 3 beneficiary trials, while amantadine and memantine each only had 2 trials showing neuropathic analgesic properties. Dextromethorphan and Valproic Acid both had 4 randomized controlled trials that showed some neuropathic treatment benefit while carbamazepine had over 8 trials showing efficacy. Finally, phenytoin only had 1 trial that showed clinical response in treatment. It is evident there are a variety of NMDA receptor antagonist agents that should be considered for treatment of neuropathic pain. Nevertheless, continued and further investigation of the 8 pharmacologic agents is needed to continue to evaluate their efficacy for treatment of neuropathic pain.

  13. Multiple doses of saw palmetto (Serenoa repens) did not alter cytochrome P450 2D6 and 3A4 activity in normal volunteers.

    PubMed

    Markowitz, John S; Donovan, Jennifer L; Devane, C Lindsay; Taylor, Robin M; Ruan, Ying; Wang, Jun-Sheng; Chavin, Kenneth D

    2003-12-01

    Saw palmetto (Serenoa repens) is the most commonly used herbal preparation in the treatment of benign prostatic hyperplasia. The objective of this study was to determine whether a characterized saw palmetto product affects the activity of cytochrome P450 (CYP) 2D6 or 3A4 in healthy volunteers (6 men and 6 women). The probe substrates dextromethorphan (CYP2D6 activity) and alprazolam (CYP3A4 activity) were administered orally at baseline and again after exposure to saw palmetto (320-mg capsule once daily) for 14 days. Dextromethorphan metabolic ratios and alprazolam pharmacokinetics were determined at baseline and after saw palmetto treatment. The mean ratio of dextromethorphan to its metabolite was 0.038 +/- 0.044 at baseline and 0.048 +/- 0.080 after 14 days of saw palmetto administration (P =.704, not significant [NS]), indicating a lack of effect on CYP2D6 activity. The area under the plasma alprazolam concentration versus time curve was 476 +/- 178 h. ng. mL(-1) at baseline and 479 +/- 125 h. ng. mL(-1) after saw palmetto treatment (P =.923, NS), indicating a lack of effect on CYP3A4 activity. The elimination half-life of alprazolam was 11.4 +/- 3.1 hours at baseline and 11.6 +/- 2.7 hours after saw palmetto treatment (P =.770, NS), also indicating a lack of effect on CYP3A4 activity. Our results indicate that extracts of saw palmetto at generally recommended doses are unlikely to alter the disposition of coadministered medications primarily dependent on the CYP2D6 or CYP3A4 pathways for elimination. These conclusions must be weighed in the context of the study's limited assessments and regarded as only the initial investigation into the drug interaction potential of saw palmetto.

  14. HPLC determination of guaifenesin with selected medications on underivatized silica with an aqueous-organic mobile phase.

    PubMed

    Wilcox, M L; Stewart, J T

    2000-10-01

    A high performance liquid chromatography procedure has been developed for the simultaneous determination of guaifenesin pseudoephedrine-dextromethorphan and guaifenesin-pseudoephedrine in commercially available capsule dosage forms and guaifenesin-codeine in a commercial cough syrup dosage form. The separation and quantitation are achieved on a 25-cm underivatized silica column using a mobile phase of 60:40%) v/v 6.25 mM phosphate buffer, pH 3.0 - acetonitrile at a flow rate of 1 ml min(-1) with detection of all analytes at 216 nm. The separation is achieved within 10 min for each drug mixture. The method showed linearity for the guaifenesin-pseudoephedrine-dextromethorphan mixture in the 50-200, 7.5-30 and 2.5-10, microg ml(-1) ranges, respectively. The intra- and inter-day RSDs ranged from 0.23 to 4.20%, 0.18 to 2.85%, and 0.13 to 5.04% for guaifenesin, pseudoephedrine, and dextromethorphan, respectively. The guaifenesin pseudoephedrine mixture yielded linear ranges of 25-100 and 3.75-15 microg ml(-1) and intra- and inter-day RSDs ranged from 0.65 to 4.18% and 0.23 to 3.00% for guaifenesin and pseudoephedrine, respectively. The method showed linearity for the guaifenesin-codeine mixture in the 25-100 and 2.5-10 microg ml(-1) ranges and RSDs ranged from 0.37 to 4.25% and 0.14 to 2.08% for guaifenesin and codeine, respectively.

  15. Complementary DNA cloning, functional expression and characterization of a novel cytochrome P450, CYP2D50, from equine liver.

    PubMed

    DiMaio Knych, H K; Stanley, S D

    2008-10-01

    Members of the CYP2D family constitute only about 2-4% of total hepatic CYP450s, however, they are responsible for the metabolism of 20-25% of commonly prescribed therapeutic compounds. CYP2D enzymes have been identified in a number of different species. However, vast differences in the metabolic activity of these enzymes have been well documented. In the horse, the presence of a member of the CYP2D family has been suggested from studies with equine liver microsomes, however its presence has not been definitively proven. In this study a cDNA encoding a novel CYP2D enzyme (CYP2D50) was cloned from equine liver and expressed in a baculovirus expression system. The nucleotide sequence of CYP2D50 was highly homologous to that of human CYP2D6 and therefore the activity of the enzyme was characterized using dextromethorphan and debrisoquine, two isoform selective substrates for the human orthologue. CYP2D50 displayed optimal catalytic activity with dextromethorphan using molar ratios of CYP2D50 to NADPH CYP450 reductase of 1:15. Although CYP2D50 and CYP2D6 shared significant sequence homology, there were striking differences in the catalytic activity between the two enzymes. CYP2D50 dextromethorphan-O-demethylase activity was nearly 180-fold slower than the human counterpart, CYP2D6. Similarly, rates of formation of 4-hydroxydebrisoquine activity were 50-fold slower for CYP2D50 compared to CYP2D6. The results of this study demonstrate substantial interspecies variability in metabolism of substrates by CYP2D orthologues in the horse and human and support the need to fully characterize this enzyme system in equids.

  16. Pharmacokinetics and metabolism of (R,R)-methoxyfenoterol in rat.

    PubMed

    Siluk, D; Mager, D E; Kim, H S; Wang, Y; Furimsky, A M; Ta, A; Iyer, L V; Green, C E; Wainer, I W

    2010-03-01

    (R,R)-fenoterol (Fen), a beta(2)-adrenoceptor agonist, is under clinical investigation in the treatment of congestive heart disease. The pharmacokinetics and metabolism of the 4-methoxyphenyl derivative of (R,R)-Fen, (R,R)-MFen, have been determined following intravenous and oral administration to the rat and compared with corresponding results obtained with (R,R)-Fen. Results from the study suggest that (R,R)-MFen can offer pharmacokinetic and metabolic advantages in comparison to an earlier (R,R)-Fen. The oral administration revealed that the net exposure of (R,R)-MFen was about three-fold higher than that of (R,R)-Fen (7.2 versus 2.3 min x nmol ml(-1)), while intravenous administration proved that the clearance was significantly reduced, 48 versus 146 ml min(-1) kg(-1), the T(1/2) was significantly longer, 152.9 versus 108.9 min, and the area under the curve (AUC) was significantly increased, 300 versus 119 min x nmol ml(-1). (R,R)-MFen was primarily cleared by glucuronidation associated with significant presystemic glucuronidation of the compound. After intravenous and oral administration of (R,R)-MFen, (R,R)-Fen and (R,R)-Fen-G were detected in the urine samples indicating that (R,R)-MFen was O-demethylated and subsequently conjugated to (R,R)-Fen-G. The total (R,R)-Fen and (R,R)-Fen-G as a percentage of the dose after intravenous administration was 3.6%, while after oral administration was 0.3%, indicating that only a small fraction of the drug escaped presystemic glucuronidation and was available for O-demethylation. The glucuronidation pattern was confirmed by the results from in vitro studies where incubation of (R,R)-MFen with rat hepatocytes produced (R,R)-MFen-G, (R,R)-Fen and (R,R)-Fen-G, while incubation with rat intestinal microsomes only resulted in the formation of (R,R)-MFen-G.

  17. Metabolism of 18-methoxycoronaridine, an ibogaine analog, to 18-hydroxycoronaridine by genetically variable CYP2C19.

    PubMed

    Zhang, Wenjiang; Ramamoorthy, Yamini; Tyndale, Rachel F; Glick, Stanley D; Maisonneuve, Isabelle M; Kuehne, Martin E; Sellers, Edward M

    2002-06-01

    18-Methoxycoronaridine, a newly developed ibogaine analog, has been reported to decrease the self-administration of morphine, cocaine, ethanol, and nicotine. It has also been reported to attenuate naltrexone-precipitated signs of morphine withdrawal. In this study, three metabolites of 18-methoxycoronaridine (18-MC) were separated and identified by high-performance liquid chromatography-electrospray ionization-mass spectrometry-mass spectrometry (HPLC-ESI-MS-MS); the major metabolite was 18-hydroxycoronaridine (18-HC). The other two metabolites were elucidated as hydroxylated metabolites on the basis of their MS-MS spectra. Catalytic studies of 18-MC O-demethylase activity in human liver microsomes indicate that one high affinity enzyme is involved in this reaction (K(m) from 2.81 to 7.9 microM; V(max) from 0.045 to 0.29 nmol/mg/min). In cDNA-expressing microsomes, only CYP2C19 displayed significant 18-MC O-demethylase activity (K(m) 1.34 microM; V(max) 0.21 nmol/mg/min). S-Mephenytoin, a selective CYP2C19 inhibitor, inhibited 18-MC O-demethylation by 65% at a concentration of 2 times its K(I), and antibodies against rat 2C (human CYP2C8, 2C9, 2C19) inhibited 18-HC formation by 70%. Studies with other cytochrome P450 (P450)-selective chemical inhibitors and antibodies failed to demonstrate an appreciable role for other P450s in this reaction. In addition, in microsomes from five different human livers, 18-MC O-demethylation correlated with S-mephenytoin 4'hydroxylase activity but not with other P450 probe reactions. These data indicate that 18-HC formation is the predominant pathway of 18-MC metabolism in vitro in human liver microsomes and that this metabolic pathway is primarily catalyzed by the polymorphic CYP2C19. The apparent selectivity of this pathway for CYP2C19 suggests 18-MC as a potentially useful probe of CYP2C19 activity in vitro and in vivo.

  18. Nanosilver particle effects on drug metabolism in vitro.

    PubMed

    Lamb, John G; Hathaway, Laura B; Munger, Mark A; Raucy, Judy L; Franklin, Michael R

    2010-12-01

    Nanosilver particles are present in consumer and health care products. Their effects on human microsomal cytochrome P450 (P450) activities and induction in luciferase reporter-engineered Caco-2 (MDR1.C) and HepG2 (DPX2 and 1A2DRE) cells have been investigated. The LD(50) values were ∼ 4 μg silver/ml for HepG2 and 5 μg/ml for Caco-2 cells. At silver concentrations that showed no decreased cell viability (<1 μg silver/ml), the pregnane X receptor (PXR)-driven 4.5-fold induction response of MDR1.C cells to 50 μM omeprazole was unaffected. In DPX2 cells, the PXR-driven 5.5- and 6.5-fold induction responses to omeprazole and 10 μM rifampicin were attenuated to 4- and 3.5-fold, respectively. Nanosilver particles alone showed no induction. In 1A2DRE cells, the aryl hydrocarbon receptor-driven 5.5-fold induction response to omeprazole was attenuated to 4-fold. In 1A2DRE cells, nanosilver alone elicited slight induction at 1 μg/ml. The inhibition of human P450-selective activities by nanosilver particles in vitro was proportional to the silver/microsomal protein ratio. At a fixed (0.5 mg/ml) protein concentration, P450-selective activities differed in sensitivity (IC(50) value). Coumarin 7-hydroxylation and 7-ethoxy-4-trifluoromethylcoumarin O-deethylation exhibited the highest IC(50) values (33.5 and 31.9 μM, respectively) and S-mephenytoin 4-hydroxylation exhibited the lowest (6.4 μM). Other IC(50) values were, in ascending order, 8.0 to 9.3 μM (testosterone 6β-hydroxylation, 7-benzyloxyquinoline debenzylation, and diclofenac 4-hydroxylation), 16.0 μM (chlorzoxazone 6-hydroxylation), 21.2 μM [7-methoxy-4-(aminomethyl)-coumarin O-demethylation], and 24.4 μM (7-methoxyresorufin O-demethylation). An investigation of 70 μM nanosilver particles showed that microsomal NADPH cytochrome c reductase activities were inhibited <12%. From our in vitro observations, we extrapolated that nanosilver particles reaching the liver may be a potential source of drug

  19. Effects of monoamine oxidase inhibitor and cytochrome P450 2D6 status on 5-Methoxy-N,N-dimethyltryptamine Metabolism and Pharmacokinetics

    PubMed Central

    Shen, Hong-Wu; Wu, Chao; Jiang, Xi-Ling; Yu, Ai-Ming

    2010-01-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural psychoactive indolealkylamine drug that has been used for recreational purpose. Our previous study revealed that polymorphic cytochrome P450 2D6 (CYP2D6) catalyzed 5-MeO-DMT O-demethylation to produce active metabolite bufotenine, while 5-MeO-DMT is mainly inactivated through deamination pathway mediated by monoamine oxidase (MAO). This study, therefore, aimed to investigate the impact of CYP2D6 genotype/phenotype status and MAO inhibitor (MAOI) on 5-MeO-DMT metabolism and pharmacokinetics. Enzyme kinetic studies using recombinant CYP2D6 allelic isozymes showed that CYP2D6.2 and CYP2D6.10 exhibited 2.6- and 40-fold lower catalytic efficiency (Vmax/Km), respectively, in producing bufotenine from 5-MeO-DMT, compared with wild-type CYP2D6.1. When co-incubated with MAOI pargyline, 5-MeO-DMT O-demethylation in 10 human liver microsomes showed significantly strong correlation with bufuralol 1’-hydroxylase activities (R² = 0.98; p < 0.0001) and CYP2D6 contents (R² = 0.77; p = 0.0007), whereas no appreciable correlations with enzymatic activities of other P450 enzymes. Furthermore, concurrent MAOI harmaline sharply reduced 5-MeO-DMT depletion and increased bufotenine formation in human CYP2D6 extensive metabolizer hepatocytes. In vivo studies in wild-type and CYP2D6-humanized (Tg-CYP2D6) mouse models showed that Tg-CYP2D6 mice receiving the same dose of 5-MeO-DMT (20 mg/kg, i.p.) had 60% higher systemic exposure to metabolite bufotenine. In addition, pre-treatment of harmaline (5 mg/kg, i.p.) led to 3.6- and 4.4-fold higher systemic exposure to 5-MeO-DMT (2 mg/kg, i.p.), and 9.9- and 6.1-fold higher systemic exposure to bufotenine in Tg-CYP2D6 and wild-type mice, respectively. These findings indicate that MAOI largely affects 5-MeO-DMT metabolism and pharmacokinetics, as well as bufotenine formation that is mediated by CYP2D6. PMID:20206139

  20. Corrinoid-Dependent Methyl Transfer Reactions Are Involved in Methanol and 3,4-Dimethoxybenzoate Metabolism by Sporomusa ovata

    PubMed Central

    Stupperich, Erhard; Konle, Ralph

    1993-01-01

    Washed and air-oxidized proteins from Sporomusa ovata cleaved the C-O bond of methanol or methoxyaromatics and transferred the methyl to dl-tetrahydrofolate. The reactions strictly required a reductive activation by titanium citrate, catalytic amounts of ATP, and the addition of dl-tetrahydrofolate. Methylcorrinoid-containing proteins carried the methanol methyl, which was transferred to dl-tetrahydrofolate at a specific rate of 120 nmol h-1 mg of protein-1. Tetrahydrofolate methylation diminished after the addition of 1-iodopropane or when the methyl donor methanol was replaced by 3,4-dimethoxybenzoate. However, whole Sporomusa cells utilize the methoxyl groups of 3,4-dimethoxybenzoate as a carbon source by a sequential O demethylation to 4-hydroxy-3-methoxybenzoate and 3,4-dihydroxybenzoate. The in vitro O demethylation of 3,4-[4-methoxyl-14C]dimethoxybenzoate proceeded via two distinct corrinoid-containing proteins to form 5-[14C]methyltetrahydrofolate at a specific rate of 200 nmol h-1 mg of protein-1. Proteins from 3,4-dimethoxybenzoate-grown cells efficiently used methoxybenzoates with vicinal substituents only, but they were unable to activate methanol. These results emphasized that specific enzymes are involved in methanol activation as well as in the activation of various methoxybenzoates and that similar corrinoid-dependent methyl transfer pathways are employed in 5-methyl-tetrahydrofolate formation from these substrates. Methyl-tetrahydrofolate could be demethylated by a distinct methyl transferase. That enzyme activity was present in washed and air-oxidized cell extracts from methanol-grown cells and from 3,4-dimethoxybenzoate-grown cells. It used cob(I)alamin as the methyl acceptor in vitro, which was methylated at a rate of 48 nmol min-1 mg of protein-1 even when ATP was omitted from the assay mixture. This methyl-cob(III)alamin formation made possible a spectrophotometric quantification of the preceding methyl transfers from methanol or

  1. Effects of monoamine oxidase inhibitor and cytochrome P450 2D6 status on 5-methoxy-N,N-dimethyltryptamine metabolism and pharmacokinetics.

    PubMed

    Shen, Hong-Wu; Wu, Chao; Jiang, Xi-Ling; Yu, Ai-Ming

    2010-07-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural psychoactive indolealkylamine drug that has been used for recreational purpose. Our previous study revealed that polymorphic cytochrome P450 2D6 (CYP2D6) catalyzed 5-MeO-DMT O-demethylation to produce active metabolite bufotenine, while 5-MeO-DMT is mainly inactivated through deamination pathway mediated by monoamine oxidase (MAO). This study, therefore, aimed to investigate the impact of CYP2D6 genotype/phenotype status and MAO inhibitor (MAOI) on 5-MeO-DMT metabolism and pharmacokinetics. Enzyme kinetic studies using recombinant CYP2D6 allelic isozymes showed that CYP2D6.2 and CYP2D6.10 exhibited 2.6- and 40-fold lower catalytic efficiency (V(max)/K(m)), respectively, in producing bufotenine from 5-MeO-DMT, compared with wild-type CYP2D6.1. When co-incubated with MAOI pargyline, 5-MeO-DMT O-demethylation in 10 human liver microsomes showed significantly strong correlation with bufuralol 1'-hydroxylase activities (R(2)=0.98; P<0.0001) and CYP2D6 contents (R(2)=0.77; P=0.0007), whereas no appreciable correlations with enzymatic activities of other P450 enzymes. Furthermore, concurrent MAOI harmaline sharply reduced 5-MeO-DMT depletion and increased bufotenine formation in human CYP2D6 extensive metabolizer hepatocytes. In vivo studies in wild-type and CYP2D6-humanized (Tg-CYP2D6) mouse models showed that Tg-CYP2D6 mice receiving the same dose of 5-MeO-DMT (20mg/kg, i.p.) had 60% higher systemic exposure to metabolite bufotenine. In addition, pretreatment of harmaline (5mg/kg, i.p.) led to 3.6- and 4.4-fold higher systemic exposure to 5-MeO-DMT (2mg/kg, i.p.), and 9.9- and 6.1-fold higher systemic exposure to bufotenine in Tg-CYP2D6 and wild-type mice, respectively. These findings indicate that MAOI largely affects 5-MeO-DMT metabolism and pharmacokinetics, as well as bufotenine formation that is mediated by CYP2D6.

  2. Inhibitory effects of psychotomimetic sigma ligands on nicotine-induced K+ flux from differentiated PC12 cells.

    PubMed

    Yamamoto, H; Sagi, N; Yamamoto, T; Goji, Y; Okuwa, M; Yoshii, M; Moroji, T

    1992-11-23

    In NGF-treated PC12 cells, nicotine-induced K+ release was measured with a K(+)-sensitive microelectrode. The K+ outflow via nicotinic ACh receptor cation channels was inhibited by various psychotomimetic sigma ligands in the sequence of PCP, dextromethorphan > DTG, MK 801, (+)SKF10047 > (+)3-PPP. The K+ release was not affected by the neuroleptic sigma ligand haloperidol nor by the calcium antagonist nifedipine. The results suggest that psychotomimetic sigma ligands inhibit nicotine-stimulated K+ flux by interacting with nicotinic, rather than via sigma 2 receptors.

  3. Pharmacological and neurophysiological aspects of space/motion sickness

    NASA Technical Reports Server (NTRS)

    Lucot, James B.; Crampton, George H.

    1991-01-01

    A motorized motion testing device modeled after a Ferris wheel was constructed to perform motion sickness tests on cats. Details of the testing are presented, and some of the topics covered include the following: xylazine-induced emesis; analysis of the constituents of the cerebrospinal fluid (CSF) during motion sickness; evaluation of serotonin-1A (5-HT sub 1A) agonists; other 5HT receptors; antimuscarinic mechanisms; and antihistaminergic mechanisms. The ability of the following drugs to reduce motion sickness in the cats was examined: amphetamines, adenosinergic drugs, opioid antagonists, peptides, cannabinoids, cognitive enhancers (nootropics), dextromethorphan/sigma ligands, scopolamine, and diphenhydramine.

  4. Drug discrimination analysis of NMDA receptor channel blockers as nicotinic receptor antagonists in rats.

    PubMed

    Zakharova, E S; Danysz, W; Bespalov, A Y

    2005-04-01

    Antagonists acting at the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors inhibit various phenomena associated with exposures to nicotine (e.g., tolerance, sensitization, dependence, and intravenous self-administration). These effects are often discussed in terms of nicotine-induced glutamate release with subsequent glutamate-dependent stimulation of dopamine metabolism and neuronal plasticity in brain areas critically involved in drug-addiction mechanisms. However, it is also well established that certain types of NMDA receptor antagonists (channel blockers) potently bind to nicotinic receptors and may act as nicotinic receptor antagonists. The present study aimed to evaluate the discriminative-stimulus effects of the NMDA receptor channel blockers (+)MK-801, dextromethorphan, and memantine in rats trained to discriminate nicotine from its vehicle. Adult male Wistar rats were trained to discriminate 0.6 mg/kg nicotine from saline under a two-lever, fixed-ratio 10 schedule of food reinforcement. During test sessions, injections of (+)MK-801 (0.03--0.3 mg/kg, i.p.), dextromethorphan (30 mg/kg, s.c.), or memantine (1--10 mg/kg, i.p.) were co-administered with s.c. nicotine (0.075--0.6 mg/kg; interaction tests) or saline (generalization tests). Additional interaction and generalization tests were conducted with the selective nicotinic receptor antagonists mecamylamine (0.1--3 mg/kg, s.c.) and MRZ 2/621 (0.3--10 mg/kg, i.p.), and the mGlu5 receptor antagonist MPEP (3--10 mg/kg, i.p.). In generalization tests, none of the compounds produced any appreciable levels of substitution for nicotine. The nicotine discriminative-stimulus control was dose dependently attenuated by mecamylamine (ED(50)=0.67 mg/kg) and MRZ 2/621 (ED(50)=9.7 mg/kg). Both agents produced a marked downward shift in the nicotine dose-response curve. Memantine and MPEP slightly attenuated nicotine discriminative-stimulus effects, while (+)MK-801 and dextromethorphan did not affect the

  5. Serum flecainide S/R ratio reflects the CYP2D6 genotype and changes in CYP2D6 activity.

    PubMed

    Doki, Kosuke; Sekiguchi, Yukio; Kuga, Keisuke; Aonuma, Kazutaka; Homma, Masato

    2015-08-01

    The aims of this study were to clarify whether the ratio of S- to R-flecainide (S/R ratio) in the serum flecainide concentration was associated with the stereoselectivity of flecainide metabolism, and to investigate the effects of the cytochrome P450 (CYP) 2D6 (CYP2D6) genotype and CYP2D6 inhibitor on the serum flecainide S/R ratio. In vitro studies using human liver microsomes and cDNA-expressed CYP isoforms suggested that variability in the serum flecainide S/R ratio was associated with the stereoselectivity of CYP2D6-mediated flecainide metabolism. We examined the serum flecainide S/R ratio in 143 patients with supraventricular tachyarrhythmia. The S/R ratio was significantly lower in intermediate metabolizers and poor metabolizers (IMs/PMs) than in extensive metabolizers (EMs) identified by the CYP2D6 genotype. The cut-off value for the S/R ratio to allow the discrimination between CYP2D6 EMs and IMs/PMs was 0.99. The S/R ratio in patients with co-administration of bepridil, a potent CYP2D6 inhibitor, was lower than 0.99, regardless of the CYP2D6 genotype status. Other factors, including age, sex, body weight, and renal function, did not affect the serum flecainide S/R ratio. This study suggests that the serum flecainide S/R ratio reflects the CYP2D6 genotype and changes in CYP2D6 activity on co-administration of a CYP2D6 inhibitor.

  6. An assessment of drug-drug interactions: the effect of desvenlafaxine and duloxetine on the pharmacokinetics of the CYP2D6 probe desipramine in healthy subjects.

    PubMed

    Patroneva, Albena; Connolly, Sandra M; Fatato, Penny; Pedersen, Ron; Jiang, Qin; Paul, Jeffrey; Guico-Pabia, Christine; Isler, Jennifer A; Burczynski, Michael E; Nichols, Alice I

    2008-12-01

    A number of antidepressants inhibit the activity of the cytochrome P450 2D6 enzyme system, which can lead to drug-drug interactions. Based on its metabolic profile, desvenlafaxine, administered as desvenlafaxine succinate, a new serotonin-norepinephrine reuptake inhibitor, is not expected to have an impact on activity of CYP2D6. This single-center, randomized, open-label, four-period, crossover study was undertaken to evaluate the effect of multiple doses of desvenlafaxine (100 mg/day, twice the recommended therapeutic dose for major depressive disorder in the United States) and duloxetine (30 mg b.i.d.) on the pharmacokinetics (PK) of a single dose of desipramine (50 mg). A single dose of desipramine was given first to assess its PK. Desvenlafaxine or duloxetine was then administered, in a crossover design, so that steady-state levels were achieved; a single dose of desipramine was then coadministered. The geometric least-square mean ratios (coadministration versus desipramine alone) for area under the plasma concentration versus time curve (AUC) and peak plasma concentrations (C(max)) of desipramine and 2-hydroxydesipramine were compared using analysis of variance. Relative to desipramine alone, increases in AUC and C(max) of desipramine associated with duloxetine administration (122 and 63%, respectively) were significantly greater than those associated with desvenlafaxine (22 and 19%, respectively; P < 0.001). Duloxetine coadministered with desipramine was also associated with a decrease in 2-hydroxydesipramine C(max) that was significant compared with the small increase seen with desvenlafaxine and desipramine (-24 versus 9%; P < 0.001); the difference between changes in 2-hydroxydesipramine AUC did not reach statistical significance (P = 0.054). Overall, desvenlafaxine had a minimal impact on the PK of desipramine compared with duloxetine, suggesting a lower risk for CYP2D6-mediated drug interactions.

  7. Desipramine, substrate for CYP2D6 activity: population pharmacokinetic model and design elements of drug–drug interaction trials

    PubMed Central

    Gueorguieva, Ivelina; Jackson, Kimberley; Wrighton, Steven A; Sinha, Vikram P; Chien, Jenny Y

    2010-01-01

    AIMS To develop a population pharmacokinetic model to describe the pharmacokinetics of desipramine in healthy subjects, after oral administration of a 50 mg dose. Additional objectives were to develop a semi-mechanistic population pharmacokinetic model for desipramine, which allowed simulation of CYP2D6-mediated inhibition, when using desipramine as a probe substrate, and to evaluate certain study design elements, such as duration of desipramine pharmacokinetic sampling, required sample size and optimal pharmacokinetic sampling schedule for intermediate, extensive and ultrarapid metabolizers of CYP2D6 substrates. RESULTS The mean population estimates of the first order absorption rate constant (ka), apparent clearance (CL/F) and apparent volume of distribution at steady state (Vss/F) were 0.15 h−1, 111 l h−1 and 2950 l, respectively. Further, using the proposed semi-mechanistic hepatic intrinsic clearance model with Bayesian inference, mean population desipramine hepatic intrinsic clearance was estimated to be 262 l h−1 with between-subject variability of 84%. d-optimal PK sampling times for intermediate metabolizers were calculated to be approximately 0.25, 24, 75 and 200 h. Similar sampling times were found for ultrarapid and extensive metabolizers except that the second d-optimal sample was earlier at 14 and 19 h, respectively, compared with 24 h for intermediate metabolizers. This difference in sampling times between the three genotypes can be attributed to the different intrinsic clearances and elimination rates. CONCLUSIONS A two compartment population pharmacokinetic model best described desipramine disposition. The semi-mechanistic population model developed is suitable to describe the pharmacokinetic behaviour of desipramine for the dose routinely used in drug–drug interaction (DDI) studies. Based on this meta-analysis of seven trials, a sample size of 21 subjects in cross-over design is appropriate for assessing CYP2D6 interaction with novel

  8. CYP3A4 and seasonal variation in vitamin D status in addition to CYP2D6 contribute to therapeutic endoxifen level during tamoxifen therapy.

    PubMed

    Teft, Wendy A; Gong, Inna Y; Dingle, Brian; Potvin, Kylea; Younus, Jawaid; Vandenberg, Theodore A; Brackstone, Muriel; Perera, Francisco E; Choi, Yun-Hee; Zou, Guangyong; Legan, Robin M; Tirona, Rommel G; Kim, Richard B

    2013-05-01

    Tamoxifen is a widely utilized adjuvant anti-estrogen agent for hormone receptor-positive breast cancer, known to undergo CYP2D6-mediated bioactivation to endoxifen. However, little is known regarding additional genetic and non-genetic determinants of optimal endoxifen plasma concentration. Therefore, 196 breast cancer patients on tamoxifen were enrolled in this prospective study over a 24-month period. Blood samples were collected for pharmacogenetic and drug-level analysis of tamoxifen and metabolites. Regression analysis indicated that besides CYP2D6, the recently described CYP3A4*22 genotype, seasonal variation, and concomitant use of CYP2D6-inhibiting antidepressants were significant predictors of endoxifen concentration. Of note, genetic variation explained 33 % of the variability while non-genetic variables accounted for 13 %. Given the proposed notion of a sub-therapeutic endoxifen concentration for predicting breast cancer recurrence, we set the therapeutic threshold at 18 nM, the 20th percentile for endoxifen level among enrolled patients in this cohort. Nearly 70 % of CYP2D6 poor metabolizers as well as extensive metabolizers on potent CYP2D6-inhibiting antidepressants exhibited endoxifen levels below 18 nM, while carriers of CYP3A4*22 were twofold less likely to be in sub-therapeutic range. Unexpectedly, endoxifen levels were 20 % lower during winter months than mean levels across seasons, which was also associated with lower vitamin D levels. CYP3A4*22 genotype along with sunshine exposure and vitamin D status may be unappreciated contributors of tamoxifen efficacy. The identified covariates along with demographic variables were integrated to create an endoxifen concentration prediction algorithm to pre-emptively evaluate the likelihood of individual patients falling below the optimal endoxifen concentration.

  9. (Bio)transformation of 2,4-dinitroanisole (DNAN) in Soils

    PubMed Central

    Olivares, Christopher I.; Abrell, Leif; Khatiwada, Raju; Chorover, Jon; Sierra-Alvarez, Reyes; Field, Jim A.

    2015-01-01

    Recent studies have begun to assess the environmental fate and toxicity of 2,4-dinitroanisole (DNAN), an insensitive munition compound of interest to defense agencies. Aerobic and anaerobic DNAN biotransformation in soils was evaluated in this study. Under aerobic conditions, there was little evidence of transformation; most observed removal was attributed to adsorption and subsequent slow chemical reactions. Under anaerobic conditions, DNAN was reductively (bio)transformed and the rate of the transformation was positively correlated with soil organic carbon (OC) up to a threshold of 2.07% OC. H2 addition enhanced the nitroreduction rate compared to endogenous treatments lacking H2. Heat-killed treatments provided rates similar to the endogenous treatment, suggesting that abiotic factors play a role in DNAN reduction. Ten (bio)transformation products were detected by high-resolution mass spectrometry. The proposed transformation pathway involves reduction of DNAN to aromatic amines, with putative reactive nitroso-intermediates coupling with the amines to form azo dimers. Secondary reactions include N-alkyl substitution, O-demethylation (sometimes followed by dehydroxylation), and removal of an N-containing group. Globally, our results suggest that the main reaction DNAN undergoes in anaerobic soils is nitroreduction to 2-methoxy-5-nitroaniline (MENA) and 2,4-diaminoanisole (DAAN), followed by anaerobic coupling reactions yielding azo-dimers. The dimers were subsequently subject to further (bio)transformations. PMID:26551225

  10. Pharmacokinetic and metabolism studies of the antiarrhythmic drug meobentine (N-(4-methoxybenzyl)-N prime , N double prime -dimethylguanidine) and its N-(4-trifluoromethyoxybenzyl)-N prime , N double prime - dimethylguanidine analogue, fluorobentine in the rat, dog and man

    SciTech Connect

    Warren, J.T.

    1988-01-01

    A radioimmunoassay (RIA) was developed that was able to detect 40 pg meobentine (M) in 0.1 ml plasma. Cross-reactivity of suspected M metabolites was very low. This RIA was later also used to assay for fluorobentine (F), a fluorine analogue of M. M exhibits three-compartment open model iv kinetics in the rat, dog, and man. Terminal drug half-life in the rat, dog, and man; total-body clearance in the rat, dog, and man; and terminal-phase volume of distribution in the rat, dog, and man were determined. (14C)-M absorption is essentially complete in the rat and dog, but this parameter could not be directly ascertained in man. Relative oral drug bioavailability is linear in the rat and dog but falls off between 5-10 mg/kg in man. F was synthesized in an attempt to counteract suspected problems with M's poor absorption or extensive metabolism that might be affecting its efficacy in humans. F would likely be unavailable for O-demethylation, might well be more lipophilic than M, and yet still be active.

  11. NPRL-Z-1, as a new topoisomerase II poison, induces cell apoptosis and ROS generation in human renal carcinoma cells.

    PubMed

    Wu, Szu-Ying; Pan, Shiow-Lin; Xiao, Zhi-Yan; Hsu, Jui-Ling; Chen, Mei-Chuan; Lee, Kuo-Hsiung; Teng, Che-Ming

    2014-01-01

    NPRL-Z-1 is a 4β-[(4"-benzamido)-amino]-4'-O-demethyl-epipodophyllotoxin derivative. Previous reports have shown that NPRL-Z-1 possesses anticancer activity. Here NPRL-Z-1 displayed cytotoxic effects against four human cancer cell lines (HCT 116, A549, ACHN, and A498) and exhibited potent activity in A498 human renal carcinoma cells, with an IC50 value of 2.38 µM via the MTT assay. We also found that NPRL-Z-1 induced cell cycle arrest in G1-phase and detected DNA double-strand breaks in A498 cells. NPRL-Z-1 induced ataxia telangiectasia-mutated (ATM) protein kinase phosphorylation at serine 1981, leading to the activation of DNA damage signaling pathways, including Chk2, histone H2AX, and p53/p21. By ICE assay, the data suggested that NPRL-Z-1 acted on and stabilized the topoisomerase II (TOP2)-DNA complex, leading to TOP2cc formation. NPRL-Z-1-induced DNA damage signaling and apoptotic death was also reversed by TOP2α or TOP2β knockdown. In addition, NPRL-Z-1 inhibited the Akt signaling pathway and induced reactive oxygen species (ROS) generation. These results demonstrated that NPRL-Z-1 appeared to be a novel TOP2 poison and ROS generator. Thus, NPRL-Z-1 may present a significant potential anticancer candidate against renal carcinoma.

  12. Liquid chromatography-tandem mass spectrometry for the identification of L-tetrahydropalmatine metabolites in Penicillium janthinellum and rats.

    PubMed

    Li, Li; Ye, Min; Bi, Kaishun; Guo, Dean

    2006-01-01

    L-tetrahydropalmatine (L-THP) is an active alkaloid from Stephania ainiaca Diels. In order to compare the similarities and differences of microbial and mammalian metabolisms of L-THP, the microbial transformation by Penicillium janthinellum and metabolism in rats were investigated. Biotransformation of L-THP by Penicillium janthinellum AS 3.510 resulted in the formation of three metabolites. Their structures were identified as L-corydalmine, L-corypalmine and 9-O-desmethyl-L-THP, respectively, by comprehensive nuclear magnetic resonance and mass spectrometry (MS) analysis. Six metabolites (M1-M6) were detected from the in vivo study in rats and three of which (L-corydalmine, L-corypalmine and 9-O-desmethyl-L-THP) were identified as the same compounds as those obtained from microbial metabolism by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis and comparison with reference standards obtained from microbial metabolism. The structures of the additional three metabolites were tentatively deduced as 2-O-desmethyl-L-THP and two di-O-demethylated L-THP by LC-MS/MS analysis. Time courses of microbial and rat metabolisms of L-THP were also investigated.

  13. Pharmacokinetics of sulfadimethoxine and sulfamethoxazole in combination with trimethoprim after oral single- and multiple-dose administration to healthy pigs.

    PubMed

    Mengelers, M J; van Gogh, E R; Huveneers, M B; Hougee, P E; Kuiper, H A; Pijpers, A; Verheijden, J H; van Miert, A S

    2001-08-01

    The pharmacokinetics were studied of sulfadimethoxine (SDM) or sulfamethoxazole (SMX) in combination with trimethoprim (TMP) administered as a single oral dose (25 mg + 5 mg per kg body weight) to two groups of 6 healthy pigs. The elimination half-lives of SMX and TMP were quite similar (2-3 h); SDM had a relatively long half-life of 13 h. Both sulfonamides (S) were exclusively metabolized to N4-acetyl derivatives but to different extents. The main metabolic pathway for TMP was O-demethylation and subsequent conjugation. In addition, the plasma concentrations of these drugs and their main metabolites after medication with different in-feed concentrations were determined. The drug (S:TMP) concentrations in the feed were 250:50, 500:100, and 1000:200 mg per kg. Steady-state concentrations were achieved within 48 h of feed medication, twice daily (SDM+TMP) or three times a day (SMX+TMP). Protein binding of SDM and its metabolite was high (>93%), whereas SMX, TMP and their metabolites showed moderate binding (48-75%). Feed medication with 500 ppm sulfonamide combined with 100 ppm TMP provided minimum steady-state plasma concentrations (C(ss,min)) higher than the concentration required for inhibition of the growth of 90% of Actinobacillus pleuropneumoniae strains (n = 20).

  14. The effect of pH on horseradish peroxidase-catalyzed oxidation of melatonin: production of N1-acetyl-N2-5-methoxykynuramine versus radical-mediated degradation.

    PubMed

    Ximenes, Valdecir F; Fernandes, João Roberto; Bueno, Vânia B; Catalani, Luiz H; de Oliveira, Georgino H; Machado, Rosângela G P

    2007-04-01

    There is a growing body of evidence that melatonin and its oxidation product, N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK), have anti-inflammatory properties. From a nutritional point of view, the discovery of melatonin in plant tissues emphasizes the importance of its relationship with plant peroxidases. Here we found that the pH of the reaction mixture has a profound influence in the reaction rate and products distribution when melatonin is oxidized by the plant enzyme horseradish peroxidase. At pH 5.5, 1 mm of melatonin was almost completely oxidized within 2 min, whereas only about 3% was consumed at pH 7.4. However, the relative yield of AFMK was higher in physiological pH. Radical-mediated oxidation products, including 2-hydroxymelatonin, a dimer of 2-hydroxymelatonin and O-demethylated dimer of melatonin account for the fast consumption of melatonin at pH 5.5. The higher production of AFMK at pH 7.4 was explained by the involvement of compound III of peroxidases as evidenced by spectral studies. On the other hand, the fast oxidative degradation at pH 5.5 was explained by the classic peroxidase cycle.

  15. Jacobsen Catalyst as a Cytochrome P450 Biomimetic Model for the Metabolism of Monensin A

    PubMed Central

    Rocha, Bruno Alves; de Oliveira, Anderson Rodrigo Moraes; Pazin, Murilo; Dorta, Daniel Junqueira; Rodrigues, Andresa Piacezzi Nascimento; Berretta, Andresa Aparecida; Peti, Ana Paula Ferranti; de Moraes, Luiz Alberto Beraldo; Lopes, Norberto Peporine; Pospíšil, Stanislav; Gates, Paul Jonathan; Assis, Marilda das Dores

    2014-01-01

    Monensin A is a commercially important natural product isolated from Streptomyces cinnamonensins that is primarily employed to treat coccidiosis. Monensin A selectively complexes and transports sodium cations across lipid membranes and displays a variety of biological properties. In this study, we evaluated the Jacobsen catalyst as a cytochrome P450 biomimetic model to investigate the oxidation of monensin A. Mass spectrometry analysis of the products from these model systems revealed the formation of two products: 3-O-demethyl monensin A and 12-hydroxy monensin A, which are the same ones found in in vivo models. Monensin A and products obtained in biomimetic model were tested in a mitochondrial toxicity model assessment and an antimicrobial bioassay against Staphylococcus aureus, S. aureus methicillin-resistant, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. Our results demonstrated the toxicological effects of monensin A in isolated rat liver mitochondria but not its products, showing that the metabolism of monensin A is a detoxification metabolism. In addition, the antimicrobial bioassay showed that monensin A and its products possessed activity against Gram-positive microorganisms but not for Gram-negative microorganisms. The results revealed the potential of application of this biomimetic chemical model in the synthesis of drug metabolites, providing metabolites for biological tests and other purposes. PMID:24987668

  16. Reductive dechlorination of methoxychlor and DDT by human intestinal bacterium Eubacterium limosum under anaerobic conditions.

    PubMed

    Yim, You-Jin; Seo, Jiyoung; Kang, Su-Il; Ahn, Joong-Hoon; Hur, Hor-Gil

    2008-04-01

    Methoxychlor [1,1,1-trichloro-2,2-bis(p-methoxyphenyl)ethane], a substitute for 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), is a compound of environmental concern because of potential long-term health risks related to its endocrine-disrupting and carcinogenic potency. In order to determine the metabolic fate of methoxychlor and DDT in the human intestinal gut, Eubacterium limosum (ATCC 8486), a strict anaerobe isolated from the human intestine that is capable of O-demethylation toward O-methylated isoflavones, was used as a model intestinal microbial organism. Under anaerobic incubation conditions, E. limosum completely transformed methoxychlor and DDT in 16 days. Based on gas chromatography-mass chromatography analyses, the metabolites produced from methoxychlor and DDT by E. limosum were confirmed to be 1,1-dichloro-2,2-bis(p-methoxyphenyl)ethane (methoxydichlor) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), respectively. This study suggests that E. limosum in the human intestinal gut might be a participant in the reductive dechlorination of methoxychlor to the more antiandrogenic active methoxydichlor.

  17. Methanogenic degradation of lignin-derived monoaromatic compounds by microbial enrichments from rice paddy field soil.

    PubMed

    Kato, Souichiro; Chino, Kanako; Kamimura, Naofumi; Masai, Eiji; Yumoto, Isao; Kamagata, Yoichi

    2015-09-24

    Anaerobic degradation of lignin-derived aromatics is an important metabolism for carbon and nutrient cycles in soil environments. Although there are some studies on degradation of lignin-derived aromatics by nitrate- and sulfate-reducing bacteria, knowledge on their degradation under methanogenic conditions are quite limited. In this study, methanogenic microbial communities were enriched from rice paddy field soil with lignin-derived methoxylated monoaromatics (vanillate and syringate) and their degradation intermediates (protocatechuate, catechol, and gallate) as the sole carbon and energy sources. Archaeal community analysis disclosed that both aceticlastic (Methanosarcina sp.) and hydrogenotrophic (Methanoculleus sp. and Methanocella sp.) methanogens dominated in all of the enrichments. Bacterial community analysis revealed the dominance of acetogenic bacteria (Sporomusa spp.) only in the enrichments on the methoxylated aromatics, suggesting that Sporomusa spp. initially convert vanillate and syringate into protocatechuate and gallate, respectively, with acetogenesis via O-demethylation. As the putative ring-cleavage microbes, bacteria within the phylum Firmicutes were dominantly detected from all of the enrichments, while the dominant phylotypes were not identical between enrichments on vanillate/protocatechuate/catechol (family Peptococcaceae bacteria) and on syringate/gallate (family Ruminococcaceae bacteria). This study demonstrates the importance of cooperation among acetogens, ring-cleaving fermenters/syntrophs and aceticlastic/hydrogenotrophic methanogens for degradation of lignin-derived aromatics under methanogenic conditions.

  18. Involvement of cytochrome P-450 enzyme activity in the selectivity and safening action of pyrazosulfuron-ethyl.

    PubMed

    Yun, M S; Shim, I S; Usui, K

    2001-03-01

    To investigate the selectivity and safening action of the sulfonylurea herbicide pyrazosulfuron-ethyl (PSE), pyrazosulfuron-ethyl O-demethylase (PSEOD) activity involving oxidative metabolism by cytochrome P-450 was studied in rice (Oryza sativa L cv Nipponbare) and Cyperus serotinus Rottb. Cytochrome P-450-dependent activity was demonstrated by the use of the inducers 1,8-naphthalic anhydride and ethanol, the herbicides PSE, bensulfuron-methyl, dimepiperate and dymron, or the inhibitor piperonyl butoxide (PBO). Growth inhibition in C serotinus seedlings was more severe than that in rice seedlings. O-Dealkylation activities of PSE were induced differently in rice and in C serotinus, with distinctly higher activity in rice seedlings. The induced PSEOD activities were slightly inhibited by PBO in rice seedlings, whereas they were strongly inhibited in C serotinus seedlings. Dimepiperate and dymron were effective safeners of rice against PSE treatment. Treatments with herbicide alone resulted in less induction of PSEOD activity compared with combined treatments of the herbicide and safener. PSEOD activity in rice seedlings induced with herbicide alone was strongly inhibited by PBO, whereas it was weakly inhibited in rice seedlings induced with combinations of PSE and two safeners. These results suggest that O-demethylation by cytochrome P-450 enzymes may be involved in the metabolism of PSE and may contribute to its selectivity and safening action. Furthermore, these results suggest the existence of a multiple form of cytochrome P-450 in plants.

  19. UPLC-ESI-Q-TOF-MS(E) identification of urinary metabolites of the emerging sport nutrition supplement methoxyisoflavone in human subjects.

    PubMed

    Lecompte, Yannick; Rosset, Martine; Richeval, Camille; Humbert, Luc; Arpino, Patrick

    2014-08-05

    Methoxyisoflavone (5-methyl-7-methoxyisoflavone) is a synthetic isoflavone used by bodybuilders for its ergogenic properties. A recent study demonstrated that methoxyisoflavone metabolites can induce false-positive results in urinary immunoassay screening tests for cannabinoids, and only one metabolite has been identified. To improve the knowledge on the metabolic pathways of methoxyisoflavone, ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF) was applied. Urine samples were obtained from methoxyisoflavone regular users. After enzymatic hydrolysis and liquid-liquid extraction, the samples were analyzed by UPLC-Q-TOF fitted with an electrospray ionization source (ESI) operating under positive ion mode. Mass data were acquired with the MS(E) method. Five metabolites were identified. Those were divided into two metabolic pathways, depending on whether the B ring hydroxylation was preceded or not by the O-demethylation of the methoxy group. The MS(E) mass spectra of methoxyisoflavone and its metabolites are specific of isoflavones structures and revealed 1,3 retro Diels-Alder fragmentation and double CO loss. Losses of small neutral molecules CO and H2O, and radical CH3, typical of flavonoids, were also observed. This study illustrates the capacity of the sensitive UPLC-Q-TOF analytical system, combined with the MS(E) method of collection of fragmentation data, to rapidly elucidate the unknown xenobiotics metabolism. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Fenpyroximate resistance in Tetranychus urticae (Acari: Tetranychidae): cross-resistance and biochemical resistance mechanisms.

    PubMed

    Kim, Young-Joon; Lee, Si-Hyeock; Lee, Si-Woo; Ahn, Young-Joon

    2004-10-01

    A field colony of the Two-spotted spider mite, Tetranychus urticae (Koch), resistant to fenpyroximate was further selected with fenpyroximate 5SC for 20 generations at a selection pressure of 30-50% mortality (designated as FR-20 strain). Resistance and cross-resistance levels of the FR-20 strain to 18 acaricides were determined using a spray method. The FR-20 strain was extremely resistant to fenpyroximate [resistance ratio (RR) 252]. The strain exhibited extremely strong positive cross-resistance to acrinathrin (RR 196), and high levels of resistance to benzoximate (RR 55) and propargite (RR 64). Moderate levels of cross-resistance (RR 11-40) to abamectin, fenbutatin oxide, fenpropathrin, pyridaben, pyridaben + bifenthrin and tebufenpyrad were observed. The FR-20 strain showed low levels of resistance (RR < 10) to azocyclotin, bromopropylate, chlorfenapyr, chlorfenapyr + bifenthrin, chlorfenapyr + pyridaben, dicofol, fenazaquin and milbemectin. Synergist experiments with different metabolic inhibitors revealed that piperonyl butoxide had the greatest effect on the efficacy of fenpyroximate, followed by iprobenfos and triphenyl phosphate. In a comparative assay with detoxifying enzymes, the FR-20 strain showed 2.5-fold higher activity in p-nitroanisole-O-demethylation, and 2.5- and 2.2-fold higher activities in alpha- and beta-naphthyl acetate hydrolysis, respectively. These results suggested that enhanced activities of both mixed-function oxidases and esterases likely contribute to the fenpyroximate resistance of the FR-20 strain of T urticae.

  1. Noribogaine (12-hydroxyibogamine): a biologically active metabolite of the antiaddictive drug ibogaine.

    PubMed

    Baumann, M H; Pablo, J P; Ali, S F; Rothman, R B; Mash, D C

    2000-09-01

    Ibogaine (IBO) is a plant-derived alkaloid that is being evaluated as a possible medication for substance use disorders. When administered peripherally to monkeys and humans, IBO is rapidly converted to an o-demethylated metabolite, 12-hydroxyibogamine (NORIBO). We have found in rats that peak blood levels of NORIBO can exceed those of the parent compound, and NORIBO persists in the bloodstream for at least 24 h. Surprisingly few studies have examined the in vivo biological activity of NORIBO. In the present series of experiments, we compared the effects of intravenous (i.v.) administration of IBO and NORIBO (1 and 10 mg/kg) on unconditioned behaviors, circulating stress hormones, and extracellular levels of dopamine (DA) and serotonin (5-HT) in the nucleus accumbens of male rats. IBO caused dose-related increases in tremors and forepaw treading, whereas NORIBO did not. Both IBO and NORIBO produced significant elevations in plasma corticosterone and prolactin, but IBO was more potent as a stimulator of corticosterone secretion. Neither drug affected extracellular DA levels in the nucleus accumbens. However, both IBO and NORIBO increased extracellular 5-HT levels, and NORIBO was more potent in this regard. The present data demonstrate that NORIBO is biologically active and undoubtedly contributes to the in vivo pharmacological profile of IBO in rats. Most importantly, NORIBO appears less likely to produce the adverse effects associated with IBO (i.e., tremors and stress-axis activation), suggesting that the metabolite may be a safer alternative for medication development.

  2. In vivo neurobiological effects of ibogaine and its O-desmethyl metabolite, 12-hydroxyibogamine (noribogaine), in rats.

    PubMed

    Baumann, M H; Rothman, R B; Pablo, J P; Mash, D C

    2001-05-01

    Ibogaine is a naturally occurring compound with purported antiaddictive properties. When administered to primates, ibogaine is rapidly o-demethylated to form the metabolite 12-hydroxyibogamine (noribogaine). Peak blood levels of noribogaine exceed those of ibogaine, and noribogaine persists in the bloodstream for at least 1 day. Very few studies have systematically evaluated the neurobiological effects of noribogaine in vivo. In the present series of experiments, we compared the effects of i.v. administration of ibogaine and noribogaine (1 and 10 mg/kg) on motor behaviors, stress hormones, and extracellular levels of dopamine (DA) and serotonin (5-HT) in the nucleus accumbens of male rats. Ibogaine caused dose-related increases in tremors, whereas noribogaine did not. Both ibogaine and noribogaine produced significant elevations in plasma corticosterone and prolactin, but ibogaine was a more potent stimulator of corticosterone secretion. Neither drug altered extracellular DA levels in the nucleus accumbens. However, both drugs increased extracellular 5-HT levels, and noribogaine was more potent in this respect. Results from in vitro experiments indicated that ibogaine and noribogaine interact with 5-HT transporters to inhibit 5-HT uptake. The present findings demonstrate that noribogaine is biologically active and undoubtedly contributes to the in vivo pharmacological profile of ibogaine in rats. Noribogaine is approximately 10 times more potent than ibogaine as an indirect 5-HT agonist. More importantly, noribogaine appears less apt to produce the adverse effects associated with ibogaine, indicating the metabolite may be a safer alternative for medication development.

  3. Biotransformation of colchicinoids into their corresponding 3-O-glucosyl derivatives by selected strains of Bacillus megaterium.

    PubMed

    Ponzone, Cesare; Berlanda, Davide; Donzelli, Fabio; Acquati, Valter; Ciulla, Rosalba; Negrini, Alberto; Rovati, Marco; Evangelista, Douglas; Fata, Emilio; Ciceri, Daniele; Perterlongo, Federico; Cabri, Walter

    2014-07-01

    Natural colchicinoids and their semisynthetic derivatives are important active ingredients for pharmaceutical applications. Thiocolchicoside (3-demethoxy-3-glucosyloxythiocolchicine) is used in several countries as standard therapy for the treatment of diseases of the muscle-skeletal system, due to its potent antiinflammatory and myorelaxant properties. Manufacturing of thiocolchicoside requires a key step, the regioselective demethylation and glucosylation of chemically derivative thiocolchicine. High selectivity and efficiency of this transformation cannot be achieved in a satisfactory way with a chemical approach. In particular, the chemical demethylation, a part from requiring toxic and aggressive reagents, generates a complex mixture of products with no industrial usefulness. We report herein an efficient, direct and green biotransformation of thiocolchicine into thiocolchicoside, performed by a specific strain of Bacillus megaterium. The same process, with minor modifications, can be used to convert the by-product 3-O-demethyl-thiocolchicine into thiocolchicoside. In addition, we describe the B. megaterium strain selection process and the best conditions for this effective double biotransformation. The final product has a pharmaceutical quality, and the process has been industrialised.

  4. Metabolism of the /sup 18/O-methoxy substituent of 3-methoxybenzoic acid and other unlabeled methoxybenzoic acids by anaerobic bacteria. [Eubacterium limosum; Acetobacterium woodil; Syntrophococcus; Clostridium; Desulfotomaculum; Enterobacter

    SciTech Connect

    DeWeerd, J.A.; Saxena, A.; Nagle, D.P. Jr.; Sulflita, J.M.

    1988-05-01

    The mechanism of the bioconversion of methoxylated benzoic acids to the hydroxylated derivatives was investigated with a model substrate and cultures of one anaerobic consortium, eight strict anaerobic bacteria, and one facultative anaerobic microorganism. We found that a haloaromatic dehalogenating consortium, a dehalogenating isolate from that consortium, Eubacterium, limosum, and a strain of Acetobacterium woodii metabolized 3-(methoxy-/sup 18/O)methoxybenzoic acid (3-anisic acid) to 3-(hydroxy-/sup 18/O)hydroxybenzoic acid stoichiometrically at rates of 1.5, 3.2, 52.4, and 36.7 nmol/min per mg of protein, respectively. A different strain of Acetobacterium and strains of Syntrophococcus, Clostridium Desulfotomaculum, Enterobacter, and an anaerobic bacterium, strain TH-001, were unable to transform this compound. The O-demethylating ability of E. limosum was induced only with appropriate methoxylated benzoates but not with D-glucose, lactate, isoleucine, or methanol. Cross-acclimation and growth experiments with E. limosum showed a rate of metabolism that was an order of magnitude slower and showed no growth with either 4-methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid) or 4-anisic acid (4-methoxybenzoic acid) when adapted to 3-anisic acid. However, A. woodii NZva-16 showed slower rates and no growth with 3- or 4-methoxysalicylic acid when adapted to 3-anisic acid in similar experiments.

  5. Parallel Post-Polyketide Synthase Modification Mechanism Involved in FD-891 Biosynthesis in Streptomyces graminofaciens A-8890.

    PubMed

    Kudo, Fumitaka; Kawamura, Koichi; Furuya, Takashi; Yamanishi, Hiroto; Motegi, Atsushi; Komatsubara, Akiko; Numakura, Mario; Miyanaga, Akimasa; Eguchi, Tadashi

    2016-02-02

    To isolate a key polyketide biosynthetic intermediate for the 16-membered macrolide FD-891 (1), we inactivated two biosynthetic genes coding for post-polyketide synthase (PKS) modification enzymes: a methyltransferase (GfsG) and a cytochrome P450 (GfsF). Consequently, FD-892 (2), which lacks the epoxide moiety at C8-C9, the hydroxy group at C10, and the O-methyl group at O-25 of FD-891, was isolated from the gfsF/gfsG double-knockout mutant. In addition, 25-O-methyl-FD-892 (3) and 25-O-demethyl-FD-891 (4) were isolated from the gfsF and gfsG mutants, respectively. We also confirmed that GfsG efficiently catalyzes the methylation of 2 and 4 in vitro. Further, GfsF catalyzed the epoxidation of the double bond at C8-C9 of 2 and 3 and subsequent hydroxylation at C10, to afford 4 and 1, respectively. These results suggest that a parallel post-PKS modification mechanism is involved in FD-891 biosynthesis.

  6. Aflatoxin B1 detoxification by CYP321A1 in Helicoverpa zea.

    PubMed

    Niu, Guodong; Wen, Zhimou; Rupasinghe, Sanjeewa G; Zeng, Ren Sen; Berenbaum, May R; Schuler, Mary A

    2008-09-01

    The polyphagous corn earworm Helicoverpa zea frequently encounters aflatoxins, mycotoxins produced by the pathogens Aspergillus flavus and A. parasiticus, which infect many of this herbivore's host plants. While aflatoxin B1 metabolism by midgut enzymes isolated from fifth instars feeding on control diets was not detected, this compound was metabolized by midgut enzymes isolated from larvae consuming diets supplemented with xanthotoxin, coumarin, or indole-3-carbinol, phytochemicals that are likely to co-occur with aflatoxin in infected host plants. Of the two metabolites generated, the main derivative identified in midguts induced with these chemicals and in reactions containing heterologously expressed CYP321A1 was aflatoxin P1 (AFP1), an O-demethylated product of AFB1. RT-PCR gel blots indicated that the magnitude of CYP321A1 transcript induction by these chemicals is associated with the magnitude of increase in the metabolic activities of induced midgut enzymes (coumarin>xanthotoxin>indole 3-carbinol). These results indicate that induction of P450s, such as CYP321A1, plays an important role in reducing AFB1 toxicity to H. zea. Docking of AFB1 in the molecular models of CYP321A1 and CYP6B8 highlights differences in their proximal catalytic site volumes that allow only CYP321A1 to generate the AFP1 metabolite. Copyright 2008 Wiley-Liss, Inc.

  7. Methanogenic degradation of lignin-derived monoaromatic compounds by microbial enrichments from rice paddy field soil

    PubMed Central

    Kato, Souichiro; Chino, Kanako; Kamimura, Naofumi; Masai, Eiji; Yumoto, Isao; Kamagata, Yoichi

    2015-01-01

    Anaerobic degradation of lignin-derived aromatics is an important metabolism for carbon and nutrient cycles in soil environments. Although there are some studies on degradation of lignin-derived aromatics by nitrate- and sulfate-reducing bacteria, knowledge on their degradation under methanogenic conditions are quite limited. In this study, methanogenic microbial communities were enriched from rice paddy field soil with lignin-derived methoxylated monoaromatics (vanillate and syringate) and their degradation intermediates (protocatechuate, catechol, and gallate) as the sole carbon and energy sources. Archaeal community analysis disclosed that both aceticlastic (Methanosarcina sp.) and hydrogenotrophic (Methanoculleus sp. and Methanocella sp.) methanogens dominated in all of the enrichments. Bacterial community analysis revealed the dominance of acetogenic bacteria (Sporomusa spp.) only in the enrichments on the methoxylated aromatics, suggesting that Sporomusa spp. initially convert vanillate and syringate into protocatechuate and gallate, respectively, with acetogenesis via O-demethylation. As the putative ring-cleavage microbes, bacteria within the phylum Firmicutes were dominantly detected from all of the enrichments, while the dominant phylotypes were not identical between enrichments on vanillate/protocatechuate/catechol (family Peptococcaceae bacteria) and on syringate/gallate (family Ruminococcaceae bacteria). This study demonstrates the importance of cooperation among acetogens, ring-cleaving fermenters/syntrophs and aceticlastic/hydrogenotrophic methanogens for degradation of lignin-derived aromatics under methanogenic conditions. PMID:26399549

  8. Influence of CYP2D6 and CYP2C19 genotypes on venlafaxine metabolic ratios and stereoselective metabolism in forensic autopsy cases.

    PubMed

    Karlsson, L; Zackrisson, A-L; Josefsson, M; Carlsson, B; Green, H; Kugelberg, F C

    2015-04-01

    We investigated whether polymorphisms in the CYP2D6 and CYP2C19 genes influence the metabolic ratios and enantiomeric S/R ratios of venlafaxine (VEN) and its metabolites O-desmethylvenlafaxine (ODV), N-desmethylvenlafaxine (NDV) and N,O-didesmethylvenlafaxine (DDV) in blood from forensic autopsy cases. In all, 94 postmortem cases found positive for VEN during toxicological screening were included. The CYP2D6 genotype was shown to significantly influence the ODV/VEN (P=0.003), DDV/NDV (P=0.010) and DDV/ODV (P=0.034) ratios. The DDV/ODV (P=0.013) and DDV/VEN (P=0.021) ratios were significantly influenced by the CYP2C19 genotype. The S/R ratios of VEN were significantly influenced by both CYP2D6 and CYP2C19 genotypes. CYP2D6 poor metabolizers (PMs) had lower S/R VEN ratios and CYP2C19 PMs had high S/R ratios of VEN in comparison. Our results show that the CYP2D6 genotype influences the O-demethylation whereas CYP2C19 influences the N-demethylation of VEN and its metabolites. In addition, we show a stereoselective metabolism where CYP2D6 favours the R-enantiomer whereas CYP2C19 favours the S-enantiomer.

  9. Characterization of metabolites of leonurine (SCM-198) in rats after oral administration by liquid chromatography/tandem mass spectrometry and NMR spectrometry.

    PubMed

    Zhu, Qing; Zhang, Jinlian; Yang, Ping; Tan, Bo; Liu, Xinhua; Zheng, Yuanting; Cai, Weimin; Zhu, Yizhun

    2014-01-01

    Leonurine, a major bioactive component from Herba Leonuri, shows therapeutic potential for cardiovascular disease and stroke prevention in some preclinical experiments. The aim of this study is to characterize metabolites of leonurine in rats using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC/MS/MS). The chromatographic separation was performed on an Agilent ZORBAX SB-C18 column using a gradient elution with acetonitrile/ammonium acetate buffer (10 mM, pH 4.0) solvent system. An information dependent acquisition (IDA) method was developed for screening and identifying metabolites of leonurine under positive ion mode. Compared with control, the interesting compound in the extracted ion chromatogram (XIC) of the in vivo samples was chosen and further identified by analyzing their retention times, changes in observed mass (Δm/z), and spectral patterns of product ion utilizing advanced software tool. For the first time, a total of three metabolites were identified, including two phase II metabolites generated by glucuronidation (M1) and sulfation (M2) and one phase I metabolite formed by O-demethylation (M3). Finally, the lead metabolite M1 was isolated from urine and its structure was characterized as leonurine-10-O- β-D-glucuronide by NMR spectroscopy (¹H, ¹³C, HMBC, and HSQC).

  10. Psychedelic 5-Methoxy-N,N-dimethyltryptamine: Metabolism, Pharmacokinetics, Drug Interactions, and Pharmacological Actions

    PubMed Central

    Shen, Hong-Wu; Jiang, Xi-Ling; Winter, Jerrold C.; Yu, Ai-Ming

    2011-01-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) belongs to a group of naturally-occurring psychoactive indolealkylamine drugs. It acts as a nonselective serotonin (5-HT) agonist and causes many physiological and behavioral changes. 5-MeO-DMT is O-demethylated by polymorphic cytochrome P450 2D6 (CYP2D6) to an active metabolite, bufotenine, while it is mainly inactivated through the deamination pathway mediated by monoamine oxidase A (MAO-A). 5-MeO-DMT is often used with MAO-A inhibitors such as harmaline. Concurrent use of harmaline reduces 5-MeO-DMT deamination metabolism and leads to a prolonged and increased exposure to the parent drug 5-MeO-DMT, as well as the active metabolite bufotenine. Harmaline, 5-MeO-DMT and bufotenine act agonistically on serotonergic systems and may result in hyperserotonergic effects or serotonin toxicity. Interestingly, CYP2D6 also has important contribution to harmaline metabolism, and CYP2D6 genetic polymorphism may cause considerable variability in the metabolism, pharmacokinetics and dynamics of harmaline and its interaction with 5-MeO-DMT. Therefore, this review summarizes recent findings on biotransformation, pharmacokinetics, and pharmacological actions of 5-MeO-DMT. In addition, the pharmacokinetic and pharmacodynamic drug-drug interactions between harmaline and 5-MeO-DMT, potential involvement of CYP2D6 pharmacogenetics, and risks of 5-MeO-DMT intoxication are discussed. PMID:20942780

  11. Identification of Manganese Superoxide Dismutase from Sphingobacterium sp. T2 as a Novel Bacterial Enzyme for Lignin Oxidation.

    PubMed

    Rashid, Goran M M; Taylor, Charles R; Liu, Yangqingxue; Zhang, Xiaoyang; Rea, Dean; Fülöp, Vilmos; Bugg, Timothy D H

    2015-10-16

    The valorization of aromatic heteropolymer lignin is an important unsolved problem in the development of a biomass-based biorefinery, for which novel high-activity biocatalysts are needed. Sequencing of the genomic DNA of lignin-degrading bacterial strain Sphingobacterium sp. T2 revealed no matches to known lignin-degrading genes. Proteomic matches for two manganese superoxide dismutase proteins were found in partially purified extracellular fractions. Recombinant MnSOD1 and MnSOD2 were both found to show high activity for oxidation of Organosolv and Kraft lignin, and lignin model compounds, generating multiple oxidation products. Structure determination revealed that the products result from aryl-Cα and Cα-Cβ bond oxidative cleavage and O-demethylation. The crystal structure of MnSOD1 was determined to 1.35 Å resolution, revealing a typical MnSOD homodimer harboring a five-coordinate trigonal bipyramidal Mn(II) center ligated by three His, one Asp, and a water/hydroxide in each active site. We propose that the lignin oxidation reactivity of these enzymes is due to the production of a hydroxyl radical, a highly reactive oxidant. This is the first demonstration that MnSOD is a microbial lignin-oxidizing enzyme.

  12. The effects of flubendazole and mebendazole on cytochromes P4501A in pheasant hepatocytes.

    PubMed

    Savlík, M; Polásková, P; Szotáková, B; Lamka, J; Skálová, L

    2005-10-01

    Many benzimidazoles are known inducers of cytochromes P4501A (CYP1A) in laboratory animals and cell lines. As flubendazole and mebendazole are benzimidazole anthelmintics often used in a pheasant, in the present study an effect of these drugs in primary cultures of pheasant (Phasianus colchicus) hepatocytes was investigated. After 48 h incubation of the hepatocytes with the benzimidazoles (0.2-5 microM), CYP1A activities -- ethoxyresorufin O-deethylation (EROD) and methoxyresorufin O-demethylation (MROD) activities were measured and the CYP1A protein levels were determined by Western blotting. None of the tested benzimidazoles influenced the CYP1A protein content. No pharmacologically significant enhancement of CYP1A after exposure of the hepatocytes to flubendazole and mebendazole was found. Inhibition of the EROD/MROD activities caused by both tested substances was observed only at the highest concentration (5 microM). From a point of view of CYP1A induction or inhibition, the treatment of pheasants by both anthelmintics tested seems to be safe. Our study demonstrates the inter-species differences in CYP1A inducibility and the importance of induction/inhibition studies on target animals.

  13. Trends in Tramadol: Pharmacology, Metabolism, and Misuse.

    PubMed

    Miotto, Karen; Cho, Arthur K; Khalil, Mohamed A; Blanco, Kirsten; Sasaki, Jun D; Rawson, Richard

    2017-01-01

    Tramadol is a unique analgesic medication, available in variety of formulations, with both monoaminergic reuptake inhibitory and opioid receptor agonist activity increasingly prescribed worldwide as an alternative for high-affinity opioid medication in the treatment of acute and chronic pain. It is a prodrug that is metabolized by cytochrome P450 (CYP) enzymes CYP2D6 and CYP3A4 to its more potent opioid analgesic metabolites, particularly the O-demethylation product M1. The opioid analgesic potency of a given dose of tramadol is influenced by an individual's CYP genetics, with poor metabolizers experiencing little conversion to the active M1 opioid metabolite and individuals with a high metabolic profile, or ultra-metabolizers, experiencing the greatest opioid analgesic effects. The importance of the CYP metabolism has led to the adoption of computer clinical decision support with pharmacogenomics tools guiding tramadol treatment in major medical centers. Tramadol's simultaneous opioid agonist action and serotonin (5-HT) and norepinephrine reuptake inhibitory effects result in a unique side effect profile and important drug interactions that must be considered. Abrupt cessation of tramadol increases the risk for both opioid and serotonin-norepinephrine reuptake inhibitor withdrawal syndromes. This review provides updated important information on the pharmacology, pharmacokinetics, CYP genetic polymorphisms, drug interactions, toxicity, withdrawal, and illicit use of tramadol.

  14. Acetylcholinesterase and carbonic anhydrase inhibitory properties of novel urea and sulfamide derivatives incorporating dopaminergic 2-aminotetralin scaffolds.

    PubMed

    Özgeriş, Bünyamin; Göksu, Süleyman; Polat Köse, Leyla; Gülçin, İlhami; Salmas, Ramin Ekhteiari; Durdagi, Serdar; Tümer, Ferhan; Supuran, Claudiu T

    2016-05-15

    In the present study a series of urea and sulfamide compounds incorporating the tetralin scaffolds were synthesized and evaluated for their acetylcholinesterase (AChE), human carbonic anhydrase (CA, EC 4.2.1.1) isoenzyme I, and II (hCA I and hCA II) inhibitory properties. The urea and their sulfamide analogs were synthesized from the reactions of 2-aminotetralins with N,N-dimethylcarbamoyl chloride and N,N-dimethylsulfamoyl chloride, followed by conversion to the corresponding phenols via O-demethylation with BBr3. The novel urea and sulfamide derivatives were tested for inhibition of hCA I, II and AChE enzymes. These derivatives exhibited excellent inhibitory effects, in the low nanomolar range, with Ki values of 2.61-3.69nM against hCA I, 1.64-2.80nM against hCA II, and in the range of 0.45-1.74nM against AChE. In silico techniques such as, atomistic molecular dynamics (MD) and molecular docking simulations, were used to understand the scenario of the inhibition mechanism upon approaching of the ligands into the active site of the target enzymes. In light of the experimental and computational results, crucial amino acids playing a role in the stabilization of the enzyme-inhibitor adducts were identified. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Marmoset cytochrome P450 2J2 mainly expressed in small intestines and livers effectively metabolizes human P450 2J2 probe substrates, astemizole and terfenadine.

    PubMed

    Uehara, Shotaro; Uno, Yasuhiro; Inoue, Takashi; Okamoto, Eriko; Sasaki, Erika; Yamazaki, Hiroshi

    2016-11-01

    1. Common marmoset (Callithrix jacchus), a New World Monkey, has potential to be a useful animal model in preclinical studies. However, drug metabolizing properties have not been fully understood due to insufficient information on cytochrome P450 (P450), major drug metabolizing enzymes. 2. Marmoset P450 2J2 cDNA was isolated from marmoset livers. The deduced amino acid sequence showed a high-sequence identity (91%) with cynomolgus monkey and human P450 2J2 enzymes. A phylogenetic tree revealed that marmoset P450 2J2 was evolutionarily closer to cynomolgus monkey and human P450 2J2 enzymes, than P450 2J forms in pigs, rabbits, rats or mice. 3. Marmoset P450 2J2 mRNA was abundantly expressed in the small intestine and liver, and to a lesser extent in the brain, lung and kidney. Immunoblot analysis also showed expression of marmoset P450 2J2 protein in the small intestine and liver. 4. Enzyme assays using marmoset P450 2J2 protein heterologously expressed in Escherichia coli indicated that marmoset P450 2J2 effectively catalyzed astemizole O-demethylation and terfenadine t-butyl hydroxylation, similar to human and cynomolgus monkey P450 2J2 enzymes. 5. These results suggest the functional characteristics of P450 2J2 enzymes are similar among marmosets, cynomolgus monkeys and humans.

  16. Small Molecule Quantification by Liquid Chromatography-Mass Spectrometry for Metabolites of Drugs and Drug CandidatesS⃞

    PubMed Central

    Dahal, Upendra P.; Davis, John A.; Rock, Dan A.

    2011-01-01

    Identification and quantification of the metabolites of drugs and drug candidates are routinely performed using liquid chromatography-mass spectrometry (LC-MS). The best practice is to generate a standard curve with the metabolite versus the internal standard. However, to avoid the difficulties in metabolite synthesis, standard curves are sometimes prepared using the substrate, assuming that the signal for substrate and the metabolite will be equivalent. We have tested the errors associated with this assumption using a series of very similar compounds that undergo common metabolic reactions using both conventional flow electrospray ionization LC-MS and low-flow captive spray ionization (CSI) LC-MS. The differences in standard curves for four different types of transformations (O-demethylation, N-demethylation, aromatic hydroxylation, and benzylic hydroxylation) are presented. The results demonstrate that the signals of the substrates compared with those of the metabolites are statistically different in 18 of the 20 substrate-metabolite combinations for both methods. The ratio of the slopes of the standard curves varied up to 4-fold but was slightly less for the CSI method. PMID:21937735

  17. Absorption and disposition of LY127210, an orally effective hypotensive agent, in laboratory animals

    SciTech Connect

    Turner, J.C.; White, J.F.; Sullivan, H.R.

    1986-03-05

    The disposition, pharmacokinetics, and metabolic fate of LY127210, 7,8-dimethoxy-(1H)-3-benzazepin-2-amine hydrochloride, have been studied in mice, rats, dogs and monkeys. Pharmacokinetic and bioavailability studies in dogs and monkeys showed it to be well absorbed orally with maximum plasma levels of drug obtained within 4 hr. Following administration of /sup 14/C-LY127210, the plasma half-lives of parent and radiocarbon in rat were 11 hr and 45 hr (..beta..-phase), respectively. In dogs and monkeys parent half-lives were 11 hr (..beta..-phase) and 5.2 hr (monophasic) while half-lives of total radiocarbon were 145 hr (..beta..-phase) and 299 hr (..beta..-phase), respectively. Plasma concentrations of parent compound in rat, dog, and monkey following oral administration accounted for approximately 15% of circulating radiocarbon. Renal excretion was the major route of elimination. The major urinary species was LY127210; metabolic mechanisms included oxidative O-demethylation and deamination, aliphatic oxidation, and reduction. Radiocarbon tissue level studies in rat indicated wide distribution of drug and/or metabolites. Similar studies in monkeys indicated that the half-life of radiocarbon in tissues was equal to or greater than that in plasma and red blood cells. The long half-life of radiocarbon in blood was due to irreversible dose dependent binding of drug and/or metabolites to plasma albumin and to cellular hemoglobin.

  18. Analgesic studies of codeine and oxycodone in patients with cancer. II. Comparisons of intramuscular oxycodone with intramuscular morphine and codeine.

    PubMed

    Beaver, W T; Wallenstein, S L; Rogers, A; Houde, R W

    1978-10-01

    The relative analgesic potency of single graded intramuscular doses of oxycodone and morphine was evaluated in a double-blind study in patients with chronic pain due to cancer. When both intensity and duration of analgesia are considered (total analgesic effect), oxycodone was 2/3 to 3/4 as potent as morphine, while in terms of peak analgesia, it was 8/10 to equipotent. In doses producing equivalent peak effect, oxycodone had a shorter duration of action than morphine. Intramuscular oxycodone was also compared to intramuscular codeine in a similar patient group. In terms of total analgesic effect, oxycodone was 10 times as potent as codeine, while in terms of peak analgesia it was 12 times as potent. These relative potency relationships of oxycodone, taken in conjunction with the oral/parenteral potency ratios of codeine and oxycodone established in the previous paper and several previous relative potency assays involving morphine, oxymorphone and codeine, demonstrate a highly consistent pattern of analgesic structure-activity relationships encompassing morphine, oxymorphone, codeine and oxycodone. The results of these studies do not appear to support the hypothesis that, in man, the analgesic activity of codeine is due to its O-demethylation to morphine.

  19. Redesign of a dioxygenase in morphine biosynthesis.

    PubMed

    Runguphan, Weerawat; Glenn, Weslee S; O'Connor, Sarah E

    2012-06-22

    Opium poppy (Papaver somniferum) produces medicinally important benzylisoquinoline alkaloids, including the analgesics codeine and morphine, in the morphinan pathway. We aligned three dioxygenases that were recently discovered in P. somniferum and subsequently identified the nonconserved regions. Two of these enzymes, codeine O-demethylase (PsCODM) and thebaine O-demethylase (PsT6ODM), are known to facilitate regioselective O-demethylation in morphinan biosynthesis. We systematically swapped the residues that were nonconserved between the PsCODM and PsT6ODM sequences to generate 16 mutant PsCODM proteins that could be overexpressed in Escherichia coli. While wild-type PsCODM can demethylate both codeine and thebaine, one engineered PsCODM mutant selectively demethylates codeine. Use of this reengineered enzyme in the reconstitution of morphine biosynthesis could selectively disable a redundant pathway branch and therefore impact the yields of the downstream products codeine and morphine in subsequent metabolic engineering efforts. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Jacobsen catalyst as a cytochrome P450 biomimetic model for the metabolism of monensin A.

    PubMed

    Rocha, Bruno Alves; de Oliveira, Anderson Rodrigo Moraes; Pazin, Murilo; Dorta, Daniel Junqueira; Rodrigues, Andresa Piacezzi Nascimento; Berretta, Andresa Aparecida; Peti, Ana Paula Ferranti; de Moraes, Luiz Alberto Beraldo; Lopes, Norberto Peporine; Pospíšil, Stanislav; Gates, Paul Jonathan; Assis, Marilda das Dores

    2014-01-01

    Monensin A is a commercially important natural product isolated from Streptomyces cinnamonensins that is primarily employed to treat coccidiosis. Monensin A selectively complexes and transports sodium cations across lipid membranes and displays a variety of biological properties. In this study, we evaluated the Jacobsen catalyst as a cytochrome P450 biomimetic model to investigate the oxidation of monensin A. Mass spectrometry analysis of the products from these model systems revealed the formation of two products: 3-O-demethyl monensin A and 12-hydroxy monensin A, which are the same ones found in in vivo models. Monensin A and products obtained in biomimetic model were tested in a mitochondrial toxicity model assessment and an antimicrobial bioassay against Staphylococcus aureus, S. aureus methicillin-resistant, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli. Our results demonstrated the toxicological effects of monensin A in isolated rat liver mitochondria but not its products, showing that the metabolism of monensin A is a detoxification metabolism. In addition, the antimicrobial bioassay showed that monensin A and its products possessed activity against Gram-positive microorganisms but not for Gram-negative microorganisms. The results revealed the potential of application of this biomimetic chemical model in the synthesis of drug metabolites, providing metabolites for biological tests and other purposes.

  1. Pathways of reductive 2,4-dinitroanisole (DNAN) biotransformation in sludge.

    PubMed

    Olivares, Christopher; Liang, Jidong; Abrell, Leif; Sierra-Alvarez, Reyes; Field, Jim A

    2013-06-01

    As the use of the insensitive munition compound 2,4-dinitroanisole (DNAN) increases, releases to the environment may pose a threat to local ecosystems. Little is known about the environmental fate of DNAN and the conversions caused by microbial activity. We studied DNAN biotransformation rates in sludge under aerobic, microaerophilic, and anaerobic conditions, detected biotransformation products, and elucidated their chemical structures. The biotransformation of DNAN was most rapid under anaerobic conditions with H2 as a cosubstrate. The results showed that the ortho nitro group in DNAN is regioselectively reduced to yield 2-methoxy-5-nitroaniline (MENA), and then the para nitro group is reduced to give 2,4-diaminoanisole (DAAN). Both MENA and DAAN were identified as important metabolites in all redox conditions. Azo and hydrazine dimer derivatives formed from the coupling of DNAN reduction products in anaerobic conditions. Secondary pathways included acetylation and methylation of amine moieties, as well as the stepwise O-demethylation and dehydroxylation of methoxy groups. Seven unique metabolites were identified which enabled elucidation of biotransformation pathways. The results taken as a whole suggest that reductive biotransformation is an important fate of DNAN leading to the formation of aromatic amines as well as azo and hydrazine dimeric metabolites. Copyright © 2012 Wiley Periodicals, Inc.

  2. Degradation of 2,4-dinitroanisole (DNAN) by metabolic cooperative activity of Pseudomonas sp. strain FK357and Rhodococcus imtechensis strain RKJ300.

    PubMed

    Khan, Fazlurrahman; Pal, Deepika; Ghosh, Anuradha; Cameotra, Swaranjit Singh

    2013-11-01

    2,4-Dinitroanisole (DNAN) is an insensitive explosive ingredient used by many defense agencies as a replacement for 2,4,6-trinitrotoluene. Although the biotransformation of DNAN under anaerobic condition has been reported, aerobic microbial degradation pathway has not been elucidated. An n-methyl-4-nitroaniline degrading bacterium Pseudomonas sp. strain FK357 transformed DNAN into 2,4-dinitrophenol (2,4-DNP) as an end product. Interestingly, when strain FK357 was co-cultured with a 2,4-DNP degrading Rhodococcus imtechensis strain RKJ300, complete and high rate of DNAN degradation was observed with no accumulation of intermediates. Enzyme assay using cell extracts of strain FK357 demonstrated that O-demethylation reaction is the first step of DNAN degradation with formation of 2,4-DNP and formaldehyde as intermediates. Subsequently, 2,4-DNP was degraded by strain RKJ300 via the formation of hydride-Meisenheimer complex. The present study clearly demonstrates that complete degradation of DNAN occurs as a result of the metabolic cooperative activity of two members within a bacterial consortium. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. (Bio)transformation of 2,4-dinitroanisole (DNAN) in soils.

    PubMed

    Olivares, Christopher I; Abrell, Leif; Khatiwada, Raju; Chorover, Jon; Sierra-Alvarez, Reyes; Field, Jim A

    2016-03-05

    Recent studies have begun to assess the environmental fate and toxicity of 2,4-dinitroanisole (DNAN), an insensitive munition compound of interest to defense agencies. Aerobic and anaerobic DNAN biotransformation in soils was evaluated in this study. Under aerobic conditions, there was little evidence of transformation; most observed removal was attributed to adsorption and subsequent slow chemical reactions. Under anaerobic conditions, DNAN was reductively (bio)transformed and the rate of the transformation was positively correlated with soil organic carbon (OC) up to a threshold of 2.07% OC. H2 addition enhanced the nitroreduction rate compared to endogenous treatments lacking H2. Heat-killed treatments provided rates similar to the endogenous treatment, suggesting that abiotic factors play a role in DNAN reduction. Ten (bio)transformation products were detected by high-resolution mass spectrometry. The proposed transformation pathway involves reduction of DNAN to aromatic amines, with putative reactive nitroso-intermediates coupling with the amines to form azo dimers. Secondary reactions include N-alkyl substitution, O-demethylation (sometimes followed by dehydroxylation), and removal of an N-containing group. Globally, our results suggest that the main reaction DNAN undergoes in anaerobic soils is nitroreduction to 2-methoxy-5-nitroaniline (MENA) and 2,4-diaminoanisole (DAAN), followed by anaerobic coupling reactions yielding azo-dimers. The dimers were subsequently subject to further (bio)transformations. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Structural identification of SAR-943 metabolites generated by human liver microsomes in vitro using mass spectrometry in combination with analysis of fragmentation patterns.

    PubMed

    Strom, Tobin; Shokati, Touraj; Klawitter, Jost; Klawitter, Jelena; Hoffman, Keith; Schiebel, Hans-Martin; Christians, Uwe

    2011-07-01

    SAR-943 (32-deoxo rapamycin) is a proliferation signal inhibitor via interaction with the mammalian target of rapamycin (mTOR). Most importantly, SAR-943 has improved chemical stability compared to rapamycin (sirolimus) and is currently under investigation as a drug coated on coronary stents. It was the goal of this study to identify the SAR-943 metabolites generated after incubation with human liver microsomes using high-resolution mass spectrometry (MS) and MS/iontrap (MS(n)) and comparison of fragmentation patterns of the metabolites with those of SAR-943 and other known rapamycin derivatives. Our study showed that SAR-943 is mainly hydroxylated and/or demethylated by human liver microsomes. The structures of the following metabolites were identified: O-demethylated metabolites: 39-O-desmethyl, 16-O-desmethyl and 27-O-desmethyl SAR-943; hydroxylated metabolites: hydroxy piperidine SAR-943, 11-hydroxy, 12-hydroxy, 14-hydroxy, 23-hydroxy, 24-hydroxy, 25-hydroxy, 46-hydroxy and 49-hydroxy SAR-943; didemethylated metabolites: 16,39-O-didesmethyl and 27,39-O-didesmethyl SAR-943; demethylated-hydroxylated metabolites: 39-O-desmethyl, 23- or 24-hydroxy and 39-O-desmethyl, hydroxy piperidine SAR-943 and dihydroxylated metabolites: 12-,23- or 24-dihydroxy SAR-943. In addition, several other demethylated-hydroxylated and dihydroxylated metabolites were detected. However, their exact structures could not be identified. Copyright © 2011 John Wiley & Sons, Ltd.

  5. Toxicokinetics of novel psychoactive substances: characterization of N-acetyltransferase (NAT) isoenzymes involved in the phase II metabolism of 2C designer drugs.

    PubMed

    Meyer, Markus R; Robert, Anja; Maurer, Hans H

    2014-06-05

    The 2,5-dimethoxyphenethylamine-derived designer drugs (so-called "2Cs") recently became of great importance on the illicit drug market as stimulating hallucinogens. They are distributed and consumed as "novel psychoactive substances" (NPS) without any safety testing at the forefront. As previous studies have shown, the 2Cs are mainly metabolized by O-demethylation, N-acetylation, or deamination. Therefore, the aim of this study was to elucidate the role of the recombinant human N-acetyltransferase (NAT) isoforms 1 and 2 in the phase II metabolism of 2Cs. For these studies, cDNA-expressed recombinant human NATs were used and formation of metabolites after incubation was measured using GC-MS. NAT2 could be shown to be the only isoform catalyzing the reaction in vitro, hence it should be the only relevant enzyme for in vivo acetylation. In general, all metabolite formation reactions followed classic Michaelis-Menten kinetics and the affinity to human NAT2 was increasing with the volume of the 4-substituent. In consequence, a slow acetylator phenotype or inhibition of NAT2 could lead to decreased N-acetylation and might lead to an increased risk of side effects caused by these novel psychoactive substances. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  6. Carbon-Carbon Bond Cleavage in Activation of the Prodrug Nabumetone

    PubMed Central

    Varfaj, Fatbardha; Zulkifli, Siti N. A.; Park, Hyoung-Goo; Challinor, Victoria L.; De Voss, James J.

    2014-01-01

    Carbon-carbon bond cleavage reactions are catalyzed by, among others, lanosterol 14-demethylase (CYP51), cholesterol side-chain cleavage enzyme (CYP11), sterol 17β-lyase (CYP17), and aromatase (CYP19). Because of the high substrate specificities of these enzymes and the complex nature of their substrates, these reactions have been difficult to characterize. A CYP1A2-catalyzed carbon-carbon bond cleavage reaction is required for conversion of the prodrug nabumetone to its active form, 6-methoxy-2-naphthylacetic acid (6-MNA). Despite worldwide use of nabumetone as an anti-inflammatory agent, the mechanism of its carbon-carbon bond cleavage reaction remains obscure. With the help of authentic synthetic standards, we report here that the reaction involves 3-hydroxylation, carbon-carbon cleavage to the aldehyde, and oxidation of the aldehyde to the acid, all catalyzed by CYP1A2 or, less effectively, by other P450 enzymes. The data indicate that the carbon-carbon bond cleavage is mediated by the ferric peroxo anion rather than the ferryl species in the P450 catalytic cycle. CYP1A2 also catalyzes O-demethylation and alcohol to ketone transformations of nabumetone and its analogs. PMID:24584631

  7. Metabolite profiling of RCS-4, a novel synthetic cannabinoid designer drug, using human hepatocyte metabolism and TOF-MS

    PubMed Central

    Gandhi, Adarsh S; Zhu, Mingshe; Pang, Shaokun; Wohlfarth, Ariane; Scheidweiler, Karl B; Huestis, Marilyn A

    2014-01-01

    Background Since 2009, scheduling legislation of synthetic cannabinoids prompted new compound emergence to circumvent legal restrictions. 2-(4-methoxyphenyl)-1-(1-pentyl-indol-3-yl)methanone (RCS-4) is a potent cannabinoid receptor agonist sold in herbal smoking blends. Absence of parent synthetic cannabinoids in urine suggests the importance of metabolite identification for detecting RCS-4 consumption in clinical and forensic investigations. Materials & methods & Results With 1 h human hepatocyte incubation and TOF high-resolution MS, we identified 18 RCS-4 metabolites, many not yet reported. Most metabolites were hydroxylated with or without demethylation, carboxylation and dealkylation followed by glucuronidation. One additional sulfated metabolite was also observed. O-demethylation was the most common biotransformation and generated the major metabolite. Conclusion For the first time, we present a metabolic scheme of RCS-4 obtained from human hepatocytes, including Phase I and II metabolites. Metabolite structural information and associated high-resolution mass spectra can be employed for developing clinical and forensic laboratory RCS-4 urine screening methods. PMID:25046048

  8. Distribution of the antifungal agents sordarins across filamentous fungi.

    PubMed

    Vicente, Francisca; Basilio, Angela; Platas, Gonzalo; Collado, Javier; Bills, Gerald F; González del Val, Antonio; Martín, Jesús; Tormo, José R; Harris, Guy H; Zink, Deborah L; Justice, Michael; Kahn, Jennifer Nielsen; Peláez, Fernando

    2009-01-01

    Sordarins are a class of natural antifungal agents which act by specifically inhibiting fungal protein synthesis through their interaction with the elongation factor 2, EF2. A number of natural sordarins produced by diverse fungi of different classes have been reported in the literature. We have run an exhaustive search of sordarin-producing fungi using two different approaches consecutively, the first one being a differential sensitivity screen using a sordarin-resistant mutant yeast strain run in parallel with a wild type strain, and the second one an empiric screen against Candida albicans followed by early detection of sordarins by LC-MS analysis. Using these two strategies we have detected as many as 22 new strains producing a number of different sordarin analogues, either known (sordarin, xylarin, zofimarin) or novel (isozofimarin and 4'-O-demethyl sordarin). Sordarin and xylarin were the most frequently found compounds in the class. The producing strains were subjected to sequencing of the ITS region to determine their phylogenetic affinities. All the strains were shown to belong to the Xylariales, being distributed across three families in this order, the Xylariaceae, the Amphisphaeriaceae, and the Diatrypaceae. Despite being screened in large numbers, we did not find sordarin production in any other fungal group, including those orders where sordarin producing fungi are known to exist (i.e., Sordariales, Eurotiales, and Microascales), suggesting that the production of sordarin is a trait more frequently associated to members of the Xylariales than to any other fungal order.

  9. Carbon-carbon bond cleavage in activation of the prodrug nabumetone.

    PubMed

    Varfaj, Fatbardha; Zulkifli, Siti N A; Park, Hyoung-Goo; Challinor, Victoria L; De Voss, James J; Ortiz de Montellano, Paul R

    2014-05-01

    Carbon-carbon bond cleavage reactions are catalyzed by, among others, lanosterol 14-demethylase (CYP51), cholesterol side-chain cleavage enzyme (CYP11), sterol 17β-lyase (CYP17), and aromatase (CYP19). Because of the high substrate specificities of these enzymes and the complex nature of their substrates, these reactions have been difficult to characterize. A CYP1A2-catalyzed carbon-carbon bond cleavage reaction is required for conversion of the prodrug nabumetone to its active form, 6-methoxy-2-naphthylacetic acid (6-MNA). Despite worldwide use of nabumetone as an anti-inflammatory agent, the mechanism of its carbon-carbon bond cleavage reaction remains obscure. With the help of authentic synthetic standards, we report here that the reaction involves 3-hydroxylation, carbon-carbon cleavage to the aldehyde, and oxidation of the aldehyde to the acid, all catalyzed by CYP1A2 or, less effectively, by other P450 enzymes. The data indicate that the carbon-carbon bond cleavage is mediated by the ferric peroxo anion rather than the ferryl species in the P450 catalytic cycle. CYP1A2 also catalyzes O-demethylation and alcohol to ketone transformations of nabumetone and its analogs.

  10. Psychedelic 5-methoxy-N,N-dimethyltryptamine: metabolism, pharmacokinetics, drug interactions, and pharmacological actions.

    PubMed

    Shen, Hong-Wu; Jiang, Xi-Ling; Winter, Jerrold C; Yu, Ai-Ming

    2010-10-01

    5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) belongs to a group of naturally-occurring psychoactive indolealkylamine drugs. It acts as a nonselective serotonin (5-HT) agonist and causes many physiological and behavioral changes. 5-MeO-DMT is O-demethylated by polymorphic cytochrome P450 2D6 (CYP2D6) to an active metabolite, bufotenine, while it is mainly inactivated through the deamination pathway mediated by monoamine oxidase A (MAO-A). 5-MeO-DMT is often used with MAO-A inhibitors such as harmaline. Concurrent use of harmaline reduces 5-MeO-DMT deamination metabolism and leads to a prolonged and increased exposure to the parent drug 5-MeO-DMT, as well as the active metabolite bufotenine. Harmaline, 5-MeO-DMT and bufotenine act agonistically on serotonergic systems and may result in hyperserotonergic effects or serotonin toxicity. Interestingly, CYP2D6 also has important contribution to harmaline metabolism, and CYP2D6 genetic polymorphism may cause considerable variability in the metabolism, pharmacokinetics and dynamics of harmaline and its interaction with 5-MeO-DMT. Therefore, this review summarizes recent findings on biotransformation, pharmacokinetics, and pharmacological actions of 5-MeO-DMT. In addition, the pharmacokinetic and pharmacodynamic drug-drug interactions between harmaline and 5-MeO-DMT, potential involvement of CYP2D6 pharmacogenetics, and risks of 5-MeO-DMT intoxication are discussed.

  11. In vitro Phase I and Phase II metabolism of α-pyrrolidinovalerophenone (α-PVP), methylenedioxypyrovalerone (MDPV) and methedrone by human liver microsomes and human liver cytosol.

    PubMed

    Negreira, Noelia; Erratico, Claudio; Kosjek, Tina; van Nuijs, Alexander L N; Heath, Ester; Neels, Hugo; Covaci, Adrian

    2015-07-01

    The aim of the present study was to identify the in vitro Phase I and Phase II metabolites of three new psychoactive substances: α-pyrrolidinovalerophenone (α-PVP), methylenedioxypyrovalerone (MDPV), and methedrone, using human liver microsomes and human liver cytosol. Accurate-mass spectra of metabolites were obtained using liquid chromatography-quadrupole time-of-flight mass spectrometry. Six Phase I metabolites of α-PVP were identified, which were formed involving reduction, hydroxylation, and pyrrolidine ring opening reactions. The lactam compound was the major metabolite observed for α-PVP. Two glucuronidated metabolites of α-PVP, not reported in previous in vitro studies, were further identified. MDPV was transformed into 10 Phase I metabolites involving reduction, hydroxylation, and loss of the pyrrolidine ring. Also, six glucuronidated and two sulphated metabolites were detected. The major metabolite of MDPV was the catechol metabolite. Methedrone was transformed into five Phase I metabolites, involving N- and O-demethylation, hydroxylation, and reduction of the ketone group. Three metabolites of methedrone are reported for the first time. In addition, the contribution of individual human CYP enzymes in the formation of the detected metabolites was investigated.

  12. Designer drug 2,4,5-trimethoxyamphetamine (TMA-2): studies on its metabolism and toxicological detection in rat urine using gas chromatographic/mass spectrometric techniques.

    PubMed

    Ewald, Andreas H; Fritschi, Giselher; Maurer, Hans H

    2006-09-01

    Studies are described on the metabolism and the toxicological detection of the amphetamine-derived designer drug 2,4,5-trimethoxyamphetamine (TMA-2) in rat urine using gas chromatographic/mass spectrometric (GC/MS) techniques. The identified metabolites indicated that TMA-2 was metabolized by oxidative deamination to the corresponding ketone followed by reduction to the corresponding alcohol, O-demethylation followed by oxidative deamination, and finally O,O-bis-demethylation. All metabolites carrying hydroxy groups were found to be partly excreted in urine as glucuronides and/or sulfates. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS after acid hydrolysis, liquid-liquid extraction, and microwave-assisted acetylation allowed the detection, in rat urine, of an intake of TMA-2 that corresponds to a common drug users' dose. Assuming similar metabolism, the described STA procedure in human urine should be suitable as proof of an intake of TMA-2. Copyright (c) 2006 John Wiley & Sons, Ltd.

  13. Biotransformation pathways of biocides and pharmaceuticals in freshwater crustaceans based on structure elucidation of metabolites using high resolution mass spectrometry.

    PubMed

    Jeon, Junho; Kurth, Denise; Hollender, Juliane

    2013-03-18

    So far, there is limited information on biotransformation mechanisms and products of polar contaminants in freshwater crustaceans. In the present study, metabolites of biocides and pharmaceuticals formed in Gammarus pulex and Daphnia magna were identified using liquid chromatography-high resolution mass spectrometry. Different confidence levels were assigned to the identification of metabolites without reference standards using a framework based on the background evidence used for structure elucidation. Twenty-five metabolites were tentatively identified for irgarol, terbutryn, tramadol, and venlafaxine in G. pulex (21 via oxidation and 4 via conjugation reactions) and 11 metabolites in D. magna (7 via oxidation and 4 via conjugation reactions), while no evidence of metabolites for clarithromycin and valsartan was found. Of the 360 metabolites predicted for the four parent compounds using pathway prediction systems and expert knowledge, 23 products were true positives, while 2 identified metabolites were unexpected products. Observed oxidative reactions included N- and O-demethylation, hydroxylation, and N-oxidation. Glutathione conjugation of selected biocides followed by subsequent reactions forming cysteine conjugates was described for the first time in freshwater invertebrates.

  14. In vitro functional assessment of 22 newly identified CYP2D6 allelic variants in the Chinese population.

    PubMed

    Dai, Da-Peng; Geng, Pei-Wu; Wang, Shuang-Hu; Cai, Jie; Hu, Li-Ming; Nie, Jing-Jing; Hu, Ji-Hong; Hu, Guo-Xin; Cai, Jian-Ping

    2015-07-01

    Cytochrome P450 2D6 (CYP2D6) is one of the most widely investigated CYPs related to genetic polymorphisms and is responsible for one-quarter of the currently used clinical drugs. We previously detected 22 novel, non-synonymous, mutated sites in the Chinese population, but nothing is known about the functional effects of these mutations in terms of specific CYP2D6 substrates. In this study, wild-type CYP2D6, two common allelic variants and 22 newly reported CYP2D6 isoforms were transiently expressed in 293FT cells, and the enzymatic activities of these variants were systematically assessed using dextromethorphan and bufuralol as the probing substrates. Consequently, 19 and 21 allelic variants were found to exhibit significantly decreased enzymatic activities for dextromethorphan and bufuralol, respectively. Of 22 novel CYP2D6 variants, six allelic isoforms (CYP2D6.89, CYP2D6.92, CYP2D6.93, CYP2D6.96, E215K and R440C) exhibited absent or extremely reduced metabolic activities compared with those observed for the wild-type enzyme. Our in vitro functional data can be useful for CYP2D6 phenotype prediction and provide valuable information for the study of clinical impact of these newly found CYP2D6 variants in China.

  15. Recommendations for the proper use of nonprescription cough suppressants and expectorants in solid-organ transplant recipients.

    PubMed

    Gabardi, Steven; Carter, Danielle; Martin, Spencer; Roberts, Keri

    2011-03-01

    To describe the pharmacology and safety of oral over-the-counter cough suppressants and expectorants and to present recommendations for the use of these agents in solid-organ transplant recipients based on the potential for adverse drug reactions or drug-disease interactions. Data from journal articles and other sources describing the pharmacology and safety of over-the-counter cough suppressants and expectorants, drug-drug interactions with immunosuppressive agents, and drug-disease state interactions are reviewed. Potential and documented drug-drug interactions between immunosuppressive agents and over-the-counter cough medications guaifenesin, dextromethorphan, diphenhydramine, and codeine were evaluated on the basis of pharmacokinetic and pharmacodynamic principles. Interactions between these cough medications and the physiological changes in the body following transplantation also were examined. Diphenhydramine requires additional monitoring when used to treat cough in transplant recipients owing to its anticholinergic properties and the potential for interactions with cyclosporine. Dextromethorphan can be used in most transplant recipients, although greater caution should be exercised if the patient has undergone liver transplant or has liver impairment. Guaifenesin can be used in transplant recipients but should be used with caution in patients receiving kidney or lung transplants and in patients with renal impairment. Codeine combined with guaifenesin is another option for cough and can be used in most transplant patients although those with reduced renal function should be monitored carefully for adverse events.

  16. From PCP to MXE: a comprehensive review of the non-medical use of dissociative drugs.

    PubMed

    Morris, Hamilton; Wallach, Jason

    2014-01-01

    PCP or phencyclidine was discovered in 1956 and soon became a popular street drug. Dissociatives including PCP, ketamine, and dextromethorphan have been used non-medically for their mind-altering effects for over 60 years. Many of these compounds have also been used clinically and in legitimate research. At least 14 derivatives of PCP were sold for non-medical and illict use from the late 1960s until the 1990s. With the advent of the Internet, the drug market underwent a dramatic evolution. While initially gray-market chemical vendors offering dextromethorphan and ketamine thrived, most recently the market has shifted to legal high and online-based research chemical vendors. Starting with the first dissociative research chemical, 4-MeO-PCP in 2008, the dissociative research chemical market has rapidly evolved and currently comprises at least 12 dissociatives, almost half of which were unknown in the scientific literature prior to their introduction. Several of these, including methoxetamine, have reached widespread use internationally. A historical account of non-medical use of over 30 dissociative compounds was compiled from a diverse collection of sources. The first complete portrait of this underground market is presented along with the relevant legal, technological, and scientific developments which have driven its evolution. Copyright © 2014 John Wiley & Sons, Ltd.

  17. Human plasma concentrations of cytochrome P450 probes extrapolated from pharmacokinetics in cynomolgus monkeys using physiologically based pharmacokinetic modeling.

    PubMed

    Shida, Satomi; Utoh, Masahiro; Murayama, Norie; Shimizu, Makiko; Uno, Yasuhiro; Yamazaki, Hiroshi

    2015-01-01

    1. Cynomolgus monkeys are widely used in preclinical studies as non-human primate species. Pharmacokinetics of human cytochrome P450 probes determined in cynomolgus monkeys after single oral or intravenous administrations were extrapolated to give human plasma concentrations. 2. Plasma concentrations of slowly eliminated caffeine and R-/S-warfarin and rapidly eliminated omeprazole and midazolam previously observed in cynomolgus monkeys were scaled to human oral biomonitoring equivalents using known species allometric scaling factors and in vitro metabolic clearance data with a simple physiologically based pharmacokinetic (PBPK) model. Results of the simplified human PBPK models were consistent with reported experimental PK data in humans or with values simulated by a fully constructed population-based simulator (Simcyp). 3. Oral administrations of metoprolol and dextromethorphan (human P450 2D probes) in monkeys reportedly yielded plasma concentrations similar to their quantitative detection limits. Consequently, ratios of in vitro hepatic intrinsic clearances of metoprolol and dextromethorphan determined in monkeys and humans were used with simplified PBPK models to extrapolate intravenous PK in monkeys to oral PK in humans. 4. These results suggest that cynomolgus monkeys, despite their rapid clearance of some human P450 substrates, could be a suitable model for humans, especially when used in conjunction with simple PBPK models.

  18. Accumulation and metabolism of drugs and CYP probe substrates in zebrafish larvae.

    PubMed

    Alderton, W; Berghmans, S; Butler, P; Chassaing, H; Fleming, A; Golder, Z; Richards, F; Gardner, I

    2010-08-01

    This study examined the accumulation and metabolism of a number of drugs and commonly used probes for human cytochrome P450s (CYPs) in zebrafish larvae under conditions relevant to pharmacological and toxicological assays. Studies with cisapride, chlorpromazine, verapamil, testosterone, and dextromethorphan showed that the zebrafish larvae catalyze a range of phase 1 (oxidation, N-demethylation, O-de-ethylation, and N-dealkylation) and phase 2 (sulfation and glucuronidation) reactions. Both similarities and differences in the metabolic pathways were observed in zebrafish larvae when compared to mammals. Metabolism of phenacetin to paracetamol and dextromethorphan to dextrorphan (metabolic reactions catalyzed by CYP 1A2 and 2D6 in humans respectively) were observed in the zebrafish larvae. In addition the zebrafish larvae 7 days post fertilization (7 d.p.f.) hydroxylated diclofenac, bupropion, tacrine, and testosterone. Although metabolites of several compounds were detected in zebrafish larvae, in the instances where the metabolite amounts were quantified, the amount of any specific metabolite formed was low, accounting for only a small percentage of the amount of parent compound added. Furthermore, when the concentrations of metabolite present in the zebrafish larvae were compared with the measured level of parent compound, the metabolite concentrations were always much lower than that of parent compound. Overall, for the compounds used in the current study it is unlikely that the quantified metabolites would significantly contribute to the outcome of safety pharmacology or toxicology studies conducted in zebrafish larvae under the paradigms typically used for such investigations.

  19. Inhibitory effects of kale ingestion on metabolism by cytochrome P450 enzymes in rats.

    PubMed

    Yamasaki, Izumi; Yamada, Masayoshi; Uotsu, Nobuo; Teramoto, Sachiyuki; Takayanagi, Risa; Yamada, Yasuhiko

    2012-01-01

    Kale (Brassica oleracea L. var acephala DC) is a leafy green vegetable belonging to the cabbage family (Brassicaceae) that contains a large amount of health-promoting phytochemicals. There are any reports about the effects of kale ingestion on the chemoprevention function and mechanism, but the interactions between kale and drugs have not been researched. We investigated the effects of kale intake on cytochrome P450 (CYP) metabolism by using cocktail probe drugs, including midazolam (for CYP3A4), caffeine (for CYP1A2), dextromethorphan (for CYP2D6), tolbutamide (for CYP2C9), omeprazole (for CYP2C19), and chlorzoxazone (for CYP2E1). Cocktail drugs were administered into rats treated with kale and cabbage (2000 mg/kg) for a week. The results showed that kale intake induced a significant increase in plasma levels and the AUC of midazolam, caffeine, and dextromethorphan. In addition, the plasma concentration and AUC of omeprazole tended to increase. Additionally, no almost differences in the mRNA expression levels of CYP enzymes in the liver were observed. In conclusion, kale ingestion was considered to have an inhibitory effect on the activities of CYP3A4, 1A2, 2D6, and 2C19 for a reason competitive inhibition than inhibitory changes in the mRNA expressions.

  20. Viscerosomatic Facilitation in a Subset of IBS Patients, an Effect Mediated by N-Methyl-D-Aspartate Receptors

    PubMed Central

    Verne, G. Nicholas; Price, Donald D; Callam, Christopher S.; Zhang, Buyi; Peck, Josh; Zhou, QiQi

    2012-01-01

    Irritable bowel syndrome (IBS) is a common gastrointestinal disorder in which the pathophysiological mechanisms of the pain and hypersensitivity are incompletely understood. IBS patients frequently complain of pain in body regions somatotopically distinct from the gut, suggesting involvement of central hyperalgesic mechanisms. We tested the role of tonic peripheral impulse input by using both repetitive thermal stimuli to the leg and repetitive stimuli to the rectum. Changes in thermal/visceral pain sensitivity after nociceptive thermal/visceral repetitive stimulation were determined. A subset of IBS patients showed enhanced rectal/thermal pain sensitivity after repetitive thermal/rectal stimulation respectively. IBS patients then received 60 mg dextromethorphan and placebo (Benadryl) in a randomized, double-blind, crossover trial. The results showed: (1) a subset of IBS patients had increased visceral/cutaneous hypersensitivity following a series of repetitive nociceptive stimuli (2) This increased pain sensitivity was blocked by administration of dextromethorphan. This is the first human study that indicates repetitive stimulation enhances a bidirectional mechanism of secondary hyperalgesia due to viscerosomatic facilitation in IBS patients. These unique findings elucidate mechanisms of somatic hypersensitivity in IBS patients and support an etiologic basis for abnormal NMDA receptor mechanisms that may be the target of future therapies for IBS. PMID:22958874

  1. Rheological characterization and drug release studies of gum exudates of Terminalia catappa Linn.

    PubMed

    Kumar, Sadhis V; Sasmal, Dinakar; Pal, Subodh C

    2008-01-01

    The present study was undertaken to evaluate the gum exudates of Terminalia catappa Linn. (TC gum) as a release retarding excipient in oral controlled drug delivery system. The rheological properties of TC gum were studied and different formulation techniques were used to evaluate the comparative drug release characteristics. The viscosity was found to be dependent on concentration and pH. Temperature up to 60 degrees C did not show significant effect on viscosity. The rheological kinetics evaluated by power law, revealed the shear thinning behavior of the TC gum dispersion in water. Matrix tablets of TC gum were prepared with the model drug dextromethorphan hydrobromide (DH) by direct compression, wet granulation and solid dispersion techniques. The dissolution profiles of the matrix tablets were compared with the pure drug containing capsules using the USP Basket apparatus with 500 ml phosphate buffer of pH 6.8 as a dissolution medium. The drug release from the compressed tablets containing TC gum was comparatively sustained than pure drug containing capsules. Even though all the formulation techniques showed reduction of dissolution rate, aqueous wet granulation showed the maximum sustained release of more than 8 h. The release kinetics estimated by the power law revealed that the drug release mechanism involved in the dextromethorphan matrix is anomalous transport as indicated by the release exponent n values. Thus the study confirmed that the TC gum might be used in the controlled drug delivery system as a release-retarding polymer.

  2. Honey for acute cough in children.

    PubMed

    Oduwole, Olabisi; Meremikwu, Martin M; Oyo-Ita, Angela; Udoh, Ekong E

    2014-12-23

    Cough causes concern for parents and is a major cause of outpatient visits. It can impact on quality of life, cause anxiety and affect sleep in parents and children. Several remedies, including honey, have been used to alleviate cough symptoms. To evaluate the effectiveness of honey for acute cough in children in ambulatory settings. We searched CENTRAL (2014, Issue 10), MEDLINE (1950 to October week 4, 2014), EMBASE (1990 to November 2014), CINAHL (1981 to November 2014), Web of Science (2000 to November 2014), AMED (1985 to November 2014), LILACS (1982 to November 2014) and CAB abstracts (2009 to January 2014). Randomised controlled trials (RCTs) comparing honey given alone, or in combination with antibiotics, versus nothing, placebo or other over-the-counter (OTC) cough medications to participants aged from one to 18 years for acute cough in ambulatory settings. Two review authors independently screened search results for eligible studies and extracted data on reported outcomes. We included three RCTs, two at high risk of bias and one at low risk of bias, involving 568 children. The studies compared honey with dextromethorphan, diphenhydramine, 'no treatment' and placebo for the effect on symptomatic relief of cough using a seven-point Likert scale. The lower the score, the better the cough symptom being assessed.Moderate quality evidence showed that honey may be better than 'no treatment' in reducing the frequency of cough (mean difference (MD) -1.05; 95% confidence interval (CI) -1.48 to -0.62; I(2) statistic 23%; two studies, 154 participants). High quality evidence also suggests that honey may be better than placebo for reduction of cough frequency (MD -1.85; 95% Cl -3.36 to -0.33; one study, 300 participants). Moderate quality evidence suggests that honey does not differ significantly from dextromethorphan in reducing cough frequency (MD -0.07; 95% CI -1.07 to 0.94; two studies, 149 participants). Low quality evidence suggests that honey may be slightly

  3. A novel incubation direct injection LC/MS/MS technique for in vitro drug metabolism screening studies involving the CYP 2D6 and the CYP 3A4 isozymes.

    PubMed

    Bhoopathy, S; Xin, B; Unger, S E; Karnes, H T

    2005-04-01

    A direct injection LC/MS/MS method involving a novel incubation technique was developed for the inhibition screening of CYP 2D6 and CYP 3A4 isoenzymes using dextromethorphan and midazolam as probe substrates. Both assays were performed using an electrospray ionization source in the positive ion mode. Direct injection was possible by using a short C 18, LC column (2 mm x 20 mm) with large particle diameter packing (10 microm). Analytical characteristics of the direct injection technique were studied by examining matrix effects, which showed suppression of the ESI signal between 0.20 and 0.65 min. The retention times for analytes were adjusted to approximately 0.8 min (k'>3), resulting in no matrix effect. Column lifetime was evaluated and determined to be approximately 160 direct injections of the matrix. The precision and accuracy of the control samples for the quantitation of dextromethorphan was between -0.53 and -12.80, and 3.73 and 6.69% respectively. Unlike conventional incubation techniques, incubations were carried out in an autosampler equipped with a heating accessory. This novel incubation method, which involved no stirring of the incubation mixture, estimated the Cl(int in vitro) for dextromethorphan and midazolam in human liver microsomes to be 1.65+/-0.22 ml/(hmg) and 0.861 ml/(min mg) respectively. The autosampler tray maintained uniform temperature and was sensitive to changes in temperature between 33 and 41 degrees C. High-throughput screening was performed using known inhibitors of the CYP 2D6 isozyme, and the system was evaluated for its ability to differentiate between these inhibitors. The strong inhibitor quinidine resulted in a 25.6% increase in t(1/2), the medium potency inhibitor chlorpromazine resulted in an increase of 6.14% and the weak inhibitor primaquine had no significant effect on half-life. This technique involves no sample preparation, demonstrated run times of 2 min per injection and can be fully automated. The method should

  4. [Pharmacology of tramadol].

    PubMed

    Dayer, P; Desmeules, J; Collart, L

    1997-01-01

    (+/-)-Tramadol is a synthetic 4-phenyl-piperidine analogue of codeine. It is a central analgesic with a low affinity for opioid receptors. Its selectivity for mu receptors has recently been demonstrated, and the M1 metabolite of tramadol, produced by liver O-demethylation, shows a higher affinity for opioid receptors than the parent drug. The rate of production of this M1 derivative (O-demethyl tramadol), is influenced by a polymorphic isoenzyme of the debrisoquine-type, cytochrome P450 2D6 (CYP2D6). Nevertheless, this affinity for mu receptors of the CNS remains low, being 6000 times lower than that of morphine. Moreover, and in contrast to other opioids, the analgesic action of tramadol is only partially inhibited by the opioid antagonist naloxone, which suggests the existence of another mechanism of action. This was demonstrated by the discovery of a monoaminergic activity that inhibits noradrenaline (norepinephrine) and serotonin (5-hydroxytryptamine; 5-HT) reuptake, making a significant contribution to the analgesic action by blocking nociceptive impulses at the spinal level. (+/-)-Tramadol is a racemic mixture of 2 enantiomers, each one displaying differing affinities for various receptors. (+/-)-Tramadol is a selective agonist of mu receptors and preferentially inhibits serotonin reuptake, whereas (-)-tramadol mainly inhibits noradrenaline reuptake. The action of these 2 enantiomers is both complementary and synergistic and results in the analgesic effect of (+/-)-tramadol. After oral administration, tramadol demonstrates 68% bioavailability, with peak serum concentrations reached within 2 hours. The elimination kinetics can be described as 2-compartmental, with a half-life of 5.1 hours for tramadol and 9 hours for the M1 derivative after a single oral dose of 100mg. This explains the approximately 2-fold accumulation of the parent drug and its M1 derivative that is observed during multiple dose treatment with tramadol. The recommended daily dose of tramadol

  5. Pharmacokinetic changes in the elderly. Do they contribute to drug abuse and dependence?

    PubMed

    Ozdemir, V; Fourie, J; Busto, U; Naranjo, C A

    1996-11-01

    The elderly frequently use psychoactive drugs including alcohol (ethanol), benzodiazepines and opioid analgesics, which have a propensity to cause abuse and dependence. Theoretically, the changes in pharmacokinetics of these agents in the elderly may modify their abuse and dependence potential. In the elderly, blood alcohol concentrations following an oral dose are higher, alcohol withdrawal syndrome follows a more severe and protracted clinical course and requires treatment with higher doses of chlordiazepoxide than needed for younger adults. However, there is no direct evidence that supports an increased direct abuse and dependence potential of alcohol because of its altered kinetics in the elderly. In the case of oxidatively metabolised benzodiazepine, both age-related pharmacokinetics and pharmacodynamic changes may increase their clinical effects in the elderly. The hypothesis that benzodiazepines have an increased abuse and dependence potential in the elderly has not been tested. Many of the benzodiazepines (e.g. alprazolam, triazolam and midazolam) are metabolised by the cytochrome P450 (CYP)3A subfamily. The pharmacokinetics of these agents may be modified by inhibition of CYP3A due to concurrently administered medications such as selective serotonin reuptake inhibitors. Unfortunately, data on the direct measures of abuse and dependence potential of benzodiazepines are not available in the elderly. Thus, a conclusive statement on the contribution of age-related pharmacokinetic changes to benzodiazepine abuse and dependence cannot be made at the present time. The clinical effects of codeine do not appear to change with age. Codeine is O-demethylated to its active metabolite morphine by the genetically polymorphic CYP2D6 isozyme. The activity of this isozyme is unaltered by age, gender or smoking habits; however, it is subject to potent inhibition by some of the frequently used medications in the elderly, such as the antidepressants paroxetine and fluoxetine

  6. Inkjet-printed selective microfluidic biosensor using CNTs functionalized by cytochrome P450 enzyme

    NASA Astrophysics Data System (ADS)

    Krivec, Matic; Leitner, Raimund; Überall, Florian; Hochleitner, Johannes

    2017-05-01

    An additive manufacturing concept, consisting of 3D photopolymer printing and Ag nanoparticle printing, was investigated for the construction of a microfluidic biosensor based on immobilized cytochrome P450 enzyme. An acylate-type microfluidic chamber composed of two parts, i.e. chamber-housing and chamber-lid was printed with a polyjet 3D printer. A 3-electrode sensor structure was inkjet-printed on the lid using a combination of Ag and graphene printing. The working electrode was covered with carbon nanotubes by drop-casting and immobilized with cytochrome P450 2D6 enzyme. The microfluidic sensor shows a significant response to a test xenobiotic, i.e. dextromethorphan; the cyclic voltammetrical measurements show a corresponding oxidation peak at 0.4 V with around 5 μM detection limit.

  7. Efficacy of levodropropizine in pediatric cough.

    PubMed

    De Blasio, Francesco; Dicpinigaitis, Peter V; De Danieli, Gianluca; Lanata, Luigi; Zanasi, Alessando

    2012-10-01

    Cough in children is among the most common problems managed by pediatricians, and occurs more frequently in preschool than in older children. Most acute episodes of cough are due to viral upper respiratory tract infections. The morbidity associated with acute cough in a child extends also to parents, teachers, and other family members and caregivers. Unfortunately, therapeutic options for acute cough in children are severely limited due to the absence of drugs shown to be effective antitussives with an acceptable safety profile. Agents used in the management of adult cough, such as narcotics (codeine, hydrocodone), the non-narcotic opioid dextromethorphan, first-generation, potentially sedating antihistamines, and decongestants such as pseudoephedrine, have all been deemed inadequate for treatment of acute pediatric cough on a risk/benefit basis. A growing body of evidence suggests that the peripherally acting antitussive, levodropropizine, may be an attractive alternative for the treatment of bothersome acute cough in children. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Therapeutic options for acute cough due to upper respiratory infections in children.

    PubMed

    Paul, Ian M

    2012-02-01

    Cough due to upper respiratory tract infections (URIs) is one of the most frequent complaints encountered by pediatric health-care providers, and one of the most disruptive symptoms for children and families. Despite the frequency of URIs, there is limited evidence to support the few therapeutic agents currently available in the United States (US) to treat acute cough due to URI. Published, well-designed, contemporary research supporting the efficacy of narcotics (codeine, hydrocodone) and US Food and Drug Administration (FDA)-approved over-the-counter (OTC) oral antitussives and expectorants (dextromethorphan, diphenhydramine, chlophedianol, and guaifenesin) is absent for URI-associated pediatric cough. Alternatively, honey and topically applied vapor rubs may be effective antitussives.

  9. Cyanide Suicide After Deep Web Shopping: A Case Report.

    PubMed

    Le Garff, Erwan; Delannoy, Yann; Mesli, Vadim; Allorge, Delphine; Hédouin, Valéry; Tournel, Gilles

    2016-09-01

    Cyanide is a product that is known for its use in industrial or laboratory processes, as well as for intentional intoxication. The toxicity of cyanide is well described in humans with rapid inhibition of cellular aerobic metabolism after ingestion or inhalation, leading to severe clinical effects that are frequently lethal. We report the case of a young white man found dead in a hotel room after self-poisoning with cyanide ordered in the deep Web. This case shows a probable complex suicide kit use including cyanide, as a lethal tool, and dextromethorphan, as a sedative and anxiolytic substance. This case is an original example of the emerging deep Web shopping in illegal drug procurement.

  10. Modular microfluidic system for emulation of human phase I/phase II metabolism.

    PubMed

    Kampe, Thomas; König, Anna; Schroeder, Hendrik; Hengstler, Jan G; Niemeyer, Christof M

    2014-03-18

    We present a microfluidic device for coupled phase I/phase II metabolic reactions in vitro. The chip consists of microchannels, which are used as packed bed reactor compartments, filled with superparamagnetic microparticles bearing recombinant microsomal phase I cytochrome P450 or phase II conjugating enzymes (UDP-glucuronosyltransferase). Online coupling of the microfluidic device with LC/MS enabled the quantitative assessment of coupled phase I/phase II transformations, as demonstrated for two different substrates, 7-benzyloxy-4-trifluoromethylcoumarin (BFC) and dextromethorphan (DEX). In contrast, conventional sequential one-pot incubations did not generate measurable amounts of phase II metabolites. Because the microfluidic device is readily assembled from standard parts and can be equipped with a variety of recombinant enzymes, it provides a modular platform to emulate and investigate hepatic metabolism processes, with particular potential for targeted small-scale synthesis and identification of metabolites formed by sequential action of specific enzymes.

  11. Analysis of pharmaceutical preparations containing antihistamine drugs by micellar liquid chromatography.

    PubMed

    Martínez-Algaba, C; Bermúdez-Saldaña, J M; Villanueva-Camañas, R M; Sagrado, S; Medina-Hernández, M J

    2006-02-13

    Rapid chromatographic procedures for analytical quality control of pharmaceutical preparations containing antihistamine drugs, alone or together with other kind of compounds are proposed. The method uses C18 stationary phases and micellar mobile phases of cetyltrimethylammonium bromide (CTAB) with either 1-propanol or 1-butanol as organic modifier. The proposed procedures allow the determination of the antihistamines: brompheniramine, chlorcyclizine, chlorpheniramine, diphenhydramine, doxylamine, flunarizine, hydroxyzine, promethazine, terfenadine, tripelennamine and triprolidine, in addition to caffeine, dextromethorphan, guaifenesin, paracetamol and pyridoxine in different pharmaceutical presentations (tablets, capsules, suppositories, syrups and ointments). The methods require minimum handling sample and are rapid (between 3 and 12 min at 1 mLmin(-1) flow rate) and reproducible (R.S.D. values<5%). Limits of detection are lower than 1 microgmL(-1) and the recoveries of the analytes in the pharmaceutical preparations are in the range 100+/-10%.

  12. Functional dyspepsia: drugs for new (and old) therapeutic targets.

    PubMed

    Cremonini, Filippo; Delgado-Aros, Silvia; Talley, Nicholas J

    2004-08-01

    The therapeutic management of functional dyspepsia remains a major challenge for the gastroenterologist. Current therapies available are based on putative underlying pathophysiologic mechanisms, including gastric acid sensitivity, slow gastric emptying and Helicobacter pylori infection, but only a small proportion of patients achieve symptomatic benefit from these therapeutic approaches. Relatively novel mechanistic concepts under testing include impaired gastric accomodation, visceral hypersensitivity, and central nervous system dysfunction. Serotonergic modulators (e.g. the 5-HT4 agonist tegaserod, the 5-HT3 antagonist alosetron and the 5-HT1P agonist sumatriptan), CCK-1 antagonists (e.g. dexloxiglumide), opioid agonists (e.g. asimadoline), N-methyl-D-aspartate (NMDA) receptor antagonists (e.g dextromethorphan), neurokinin antagonists (e.g. talnetant), capsaicin-like agents and antidepressants are among the agents currently under investigation. It seems unlikely, however, that targeting a single mechanism with an individual drug will result in complete symptom remission in most cases.

  13. Selective involvement of kappa opioid and phencyclidine receptors in the analgesic and motor effects of dynorphin-A-(1-13)-Tyr-Leu-Phe-Asn-Gly-Pro.

    PubMed

    Shukla, V K; Bansinath, M; Dumont, M; Lemaire, S

    1992-09-18

    Dynorphin A-(1-13)-Tyr-Leu-Phe-Asn-Gly-Pro (Dyn Ia; 1-8 nmol) injected intracerebroventricularly in the mouse produces two independent behavioral effects: (1) a norbinaltorphimine (kappa opioid antagonist)-reversible analgesia in the acetic acid-induced writhing test and (2) motor dysfunction characterized by wild running, pop-corn jumping, hindlimb jerking and barrel rolling and antagonized by the irreversible phencyclidine (PCP) and sigma (sigma) receptor antagonist, metaphit and the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists, dextromethorphan and ketamine. The specific involvement of the PCP receptor in the motor effects of Dyn Ia is supported by the direct competitive interaction of the peptide with the binding of [3H]MK-801 (Ki: 0.63 microM) and [3H]TCP (Ki: 4.6 microM) to mouse brain membrane preparations.

  14. EEG with extreme delta brush in young female with methotrexate neurotoxicity supports NMDA receptor involvement.

    PubMed

    Schmidt, Lisbeth Samsø; Kjær, Troels W; Schmiegelow, Kjeld; Born, Alfred Peter

    2017-09-01

    Sub-acute neurotoxicity is a well-known complication to high-dose and intrathecal methotrexate (MTX) treatment of children with leukemia. Symptoms can be treated safely by dextromethorphan, a non-competitive antagonist to N-methyl-D-aspartic acid receptor (NMDAR). In a female with subacute MTX neurotoxicity, we observed an electroencephalographic (EEG) with extreme delta brush. Extreme delta brush is an EEG pattern previously described in patients with NMDAR autoimmune encephalitis. The observations suggest that the mechanism of this neurotoxicity may be mediated by the NMDAR. Furthermore, extreme EEG delta brush should suggest a diagnosis of MTX associated subacute neurotoxicity. Copyright © 2017 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  15. Anti-Yo Mediated Paraneoplastic Cerebellar Degeneration Associated with Pseudobulbar Affect in a Patient with Breast Cancer

    PubMed Central

    Martin, Allison N.; Jones, David E.; Brenin, David R.; Lapides, David A.

    2017-01-01

    Paraneoplastic cerebellar degeneration (PCD) is a rare anti-Yo mediated paraneoplastic syndromes rarely that is infrequently associated with breast cancer. We present a case of a 52-year-old female presenting with diplopia, gait instability, dysarthria, dysphagia, nystagmus, and, most notably, new onset paroxysmal episodes of uncontrollable crying concerning for pseudobulbar affect (PBA). Serologic testing showed anti-Yo antibodies. The patient was found to have stage IIIA breast cancer as the inciting cause of the paraneoplastic syndrome. The patient was treated with neoadjuvant chemotherapy, modified radical mastectomy, adjuvant Herceptin, and pertuzumab. She was given IVIG for paraneoplastic syndrome, antidepressants, and dextromethorphan-quinidine (Nuedexta), the first FDA-approved therapy for PBA. With multimodality therapy, she demonstrated significant improvement in neurologic and mood symptoms associated with PCD and PBA. PMID:28377827

  16. Drugs and Alcohol in Civil Aviation Accident Pilot Fatalities from 2004-2008

    DTIC Science & Technology

    2011-09-01

    1989 Doxylamine 8 0.4 15 0.9 19 1.2 12 0.9 FDA 򒾅 Ephedrine 1 0.1 47 2.8 74 4.7 29 2.1 FDA 򒾅 Guaiphenesin 0 0.0 1 0.1 0 0.0 0 0.0 FDA...Dextromethorphan/Metabolites 4 0.2 26 1.5 20 1.3 16 1.2 FDA 򒾅 Doxylamine 8 0.4 15 0.9 19 1.2 12 0.9 FDA 򒾅 Ephedrine 1 0.1 47 2.8 74 4.7 29 2.1 FDA

  17. Separation of cold medicine ingredients using a precise MEKC method at elevated pH.

    PubMed

    Hasemann, Phillip; ter Balk, Marieke; Preu, Lutz; Wätzig, Hermann

    2007-06-01

    An MEKC method was developed in order to separate a cold medicine formulation containing acetaminophen, ephedrine sulfate, doxylamine succinate, and dextromethorphan hydrobromide as active pharmaceutical ingredients. Because of their similar physical and chemical properties, it was a challenge to separate the basic compounds without sample pretreatment. In addition, the high content of alcohol and sucrose together with the variety of further excipients had to be considered. Thus, the complex matrix required several optimization steps. These included the search for the optimum pH and for a suitable sodium dodecyl sulfate concentration to avoid matrix-capillary wall interaction and to ensure precision. As a second developing step, an internal standard (benzocaine) was chosen to guarantee a high level of quantitative performance. An RSD% value of the peak areas between 1.0 and 2.0 was reached. The employed method development strategy can be generalized to similar separation approaches in the future.

  18. Detection of an endogenous urinary biomarker associated with CYP2D6 activity using global metabolomics

    PubMed Central

    Tay-Sontheimer, Jessica; Shireman, Laura M; Beyer, Richard P; Senn, Taurence; Witten, Daniela; Pearce, Robin E; Gaedigk, Andrea; Fomban, Cletus L Gana; Lutz, Justin D; Isoherranen, Nina; Thummel, Kenneth E; Fiehn, Oliver; Leeder, J Steven; Lin, Yvonne S

    2015-01-01

    Aim We sought to discover endogenous urinary biomarkers of human CYP2D6 activity. Patients & methods Healthy pediatric subjects (n = 189) were phenotyped using dextromethorphan and randomized for candidate biomarker selection and validation. Global urinary metabolomics was performed using liquid chromatography quadrupole time-of-flight mass spectrometry. Candidate biomarkers were tested in adults receiving fluoxetine, a CYP2D6 inhibitor. Results A biomarker, M1 (m/z 444.3102) was correlated with CYP2D6 activity in both the pediatric training and validation sets. Poor metabolizers had undetectable levels of M1, whereas it was present in subjects with other phenotypes. In adult subjects, a 9.56-fold decrease in M1 abundance was observed during CYP2D6 inhibition. Conclusion Identification and validation of M1 may provide a noninvasive means of CYP2D6 phenotyping. PMID:25521354

  19. Infants and young children metabolise codeine to morphine. A study after single and repeated rectal administration.

    PubMed Central

    Quiding, H; Olsson, G L; Boreus, L O; Bondesson, U

    1992-01-01

    1. Codeine was administered rectally to thirteen infants and young children undergoing elective surgery. Nine infants (6-10 months old) received a 4 mg suppository and four children (3-4 years old) an 8 mg suppository. Codeine and its metabolite morphine were measured in plasma by GC/MS. 2. The mean concentrations of codeine at 3, 4 and 5 h after administration were 240, 163 and 123 nmol l-1 in the younger and 309, 251 and 169 nmol l-1 in the older patients. The corresponding concentrations of morphine were 8.3, 7.4 and 4.5 nmol l-1 and 6.8, 5.5 and 2.8 nmol l-1 respectively. One patient in each age group had no detectable amounts of morphine. 3. In the four children, the rectal dose was repeated 6-hourly for four doses. The plasma concentrations of codeine and morphine following the fifth dose were similar to those after the first dose. The mean AUC(0,5 h) of morphine was 1.6% that of codeine. 4. In the infants the mean plasma half-lives of codeine and morphine were 2.6 and 2.5 h. The two infants with the lowest body weights had the longest half-lives. 5. The mean morphine/codeine concentration ratio was 4.3% in the infants and 1.6% in the children, suggesting impaired glucuronidation of morphine in the former group. The hourly concentration ratios were almost identical following the first and fifth dose in the children. 6. We conclude that at the age of 6 months infants are capable of O-demethylating codeine to morphine. PMID:1540490

  20. Identification of new oxycodone metabolites in human urine by capillary electrophoresis-multiple-stage ion-trap mass spectrometry.

    PubMed

    Baldacci, A; Caslavska, J; Wey, A B; Thormann, W

    2004-10-08

    Capillary electrophoresis-electrospray ionization multiple-stage ion-trap mass spectrometry (CE-MSn) and computer simulation of fragmentation are demonstrated to be effective tools to detect and identify phase I and phase II metabolites of oxycodone (OCOD) in human urine. OCOD is a strong analgesic used for the management of moderate to severe mainly postoperative or cancer-related pain whose metabolism in man is largely unknown. Using an aqueous pH 9 ammonium acetate buffer and CE-MSn (n < or = 5), OCOD and its phase I metabolites produced by O-demethylation, N-demethylation, 6-ketoreduction and N-oxidation (such as oxymorphone, noroxycodone, noroxymorphone, 6-oxycodol, nor-6-oxycodol, oxycodone-N-oxide and 6-oxycodol-N-oxide) and phase II conjugates with glucuronic acid of several of these compounds could be detected in alkaline solid-phase extracts of a patient urine that was collected during a pharmacotherapy episode with daily ingestion of 240-320 mg of OCOD chloride. The data for three known OCOD metabolites for which the standards had to be synthesized in-house, 6-oxycodol, nor-6-oxycodol and oxycodone-N-oxide, were employed to identify two new metabolites, the N-oxidized derivative of 6-oxycodol and an O-glucuronide of this compound. CE-MSn and computer simulation of fragmentation also led to the identification of the N-glucuronide of noroxymorphone, another novel OCOD metabolite for which no standard compound or mass spectra library data were available.

  1. Forensic drug testing for opiates. VI. Urine testing for hydromorphone, hydrocodone, oxymorphone, and oxycodone with commercial opiate immunoassays and gas chromatography-mass spectrometry.

    PubMed

    Smith, M L; Hughes, R O; Levine, B; Dickerson, S; Darwin, W D; Cone, E J

    1995-01-01

    Opiate testing for morphine and codeine is performed routinely in forensic urine drug-testing laboratories in an effort to identify illicit opiate abusers. In addition to heroin, the 6-keto-opioids, including hydromorphone, hydrocodone, oxymorphone, and oxycodone, have high abuse liability and are self-administered by opiate abusers, but only limited information is available on detection of these compounds by current immunoassay and gas chromatographic-mass spectrometric (GC-MS) methods. In this study, single doses of hydromorphone, hydrocodone, oxymorphone, and oxycodone were administered to human subjects, and urine samples were collected before and periodically after dosing. Opiate levels were determined in a quantitative mode with four commercial immunoassays, TDx opiates (TDx), Abuscreen radioimmunoassay (ABUS), Coat-A-Count morphine in urine (CAC), and EMIT d.a.u. opiate assay (EMIT), and by GC-MS. GC-MS assay results indicated that hydromorphone, hydrocodone, oxymorphone, and oxycodone administration resulted in rapid excretion of parent drug and O-demethylated metabolites in urine. Peak concentrations occurred within 8 h after drug administration and declined below 300 ng/mL within 24-48 h. Immunoassay testing indicated that hydromorphone, hydrocodone, and oxycodone, but not oxymorphone, were detectable in urine by TDx and EMIT (300-ng/mL cutoff) for 6-24 h. ABUS detected only hydrocodone, and CAC failed to detect any of the four 6-keto-opioid analgesics. Generally, immunoassays for opiates in urine displayed substantially lower sensitivities for 6-keto-opioids compared with GC-MS. Consequently, urine samples containing low to moderate concentrations of hydromorphone, hydrocodone, oxymorphone, and oxycodone will likely go undetected when tested by conventional immunoassays.

  2. Acetogenic and sulfate-reducing bacteria inhabiting the rhizoplane and deep cortex cells of the sea grass Halodule wrightii.

    PubMed

    Küsel, K; Pinkart, H C; Drake, H L; Devereux, R

    1999-11-01

    Recent declines in sea grass distribution underscore the importance of understanding microbial community structure-function relationships in sea grass rhizospheres that might affect the viability of these plants. Phospholipid fatty acid analyses showed that sulfate-reducing bacteria and clostridia were enriched in sediments colonized by the sea grasses Halodule wrightii and Thalassia testudinum compared to an adjacent unvegetated sediment. Most-probable-number analyses found that in contrast to butyrate-producing clostridia, acetogens and acetate-utilizing sulfate reducers were enriched by an order of magnitude in rhizosphere sediments. Although sea grass roots are oxygenated in the daytime, colorimetric root incubation studies demonstrated that acetogenic O-demethylation and sulfidogenic iron precipitation activities were tightly associated with washed, sediment-free H. wrightii roots. This suggests that the associated anaerobes are able to tolerate exposure to oxygen. To localize and quantify the anaerobic microbial colonization, root thin sections were hybridized with newly developed (33)P-labeled probes that targeted (i) low-G+C-content gram-positive bacteria, (ii) cluster I species of clostridia, (iii) species of Acetobacterium, and (iv) species of Desulfovibrio. Microautoradiography revealed intercellular colonization of the roots by Acetobacterium and Desulfovibrio species. Acetogenic bacteria occurred mostly in the rhizoplane and outermost cortex cell layers, and high numbers of sulfate reducers were detected on all epidermal cells and inward, colonizing some 60% of the deepest cortex cells. Approximately 30% of epidermal cells were colonized by bacteria that hybridized with an archaeal probe, strongly suggesting the presence of methanogens. Obligate anaerobes within the roots might contribute to the vitality of sea grasses and other aquatic plants and to the biogeochemistry of the surrounding sediment.

  3. Acetogenic and Sulfate-Reducing Bacteria Inhabiting the Rhizoplane and Deep Cortex Cells of the Sea Grass Halodule wrightii†

    PubMed Central

    Küsel, Kirsten; Pinkart, Holly C.; Drake, Harold L.; Devereux, Richard

    1999-01-01

    Recent declines in sea grass distribution underscore the importance of understanding microbial community structure-function relationships in sea grass rhizospheres that might affect the viability of these plants. Phospholipid fatty acid analyses showed that sulfate-reducing bacteria and clostridia were enriched in sediments colonized by the sea grasses Halodule wrightii and Thalassia testudinum compared to an adjacent unvegetated sediment. Most-probable-number analyses found that in contrast to butyrate-producing clostridia, acetogens and acetate-utilizing sulfate reducers were enriched by an order of magnitude in rhizosphere sediments. Although sea grass roots are oxygenated in the daytime, colorimetric root incubation studies demonstrated that acetogenic O-demethylation and sulfidogenic iron precipitation activities were tightly associated with washed, sediment-free H. wrightii roots. This suggests that the associated anaerobes are able to tolerate exposure to oxygen. To localize and quantify the anaerobic microbial colonization, root thin sections were hybridized with newly developed 33P-labeled probes that targeted (i) low-G+C-content gram-positive bacteria, (ii) cluster I species of clostridia, (iii) species of Acetobacterium, and (iv) species of Desulfovibrio. Microautoradiography revealed intercellular colonization of the roots by Acetobacterium and Desulfovibrio species. Acetogenic bacteria occurred mostly in the rhizoplane and outermost cortex cell layers, and high numbers of sulfate reducers were detected on all epidermal cells and inward, colonizing some 60% of the deepest cortex cells. Approximately 30% of epidermal cells were colonized by bacteria that hybridized with an archaeal probe, strongly suggesting the presence of methanogens. Obligate anaerobes within the roots might contribute to the vitality of sea grasses and other aquatic plants and to the biogeochemistry of the surrounding sediment. PMID:10543830

  4. Bioactivation of the citrus flavonoid nobiletin by CYP1 enzymes in MCF7 breast adenocarcinoma cells.

    PubMed

    Surichan, Somchaiya; Androutsopoulos, Vasilis P; Sifakis, Stavros; Koutala, Eleni; Tsatsakis, Aristidis; Arroo, Randolph R J; Boarder, Michael R

    2012-09-01

    Recent studies have demonstrated cytochrome P450 CYP1-mediated metabolism and CYP1-enzyme induction by naturally occurring flavonoids in cancer cell line models. The arising metabolites often exhibit higher activity than the parent compound. In the present study we investigated the CYP1-mediated metabolism of the citrus polymethoxyflavone nobiletin by recombinant CYP1 enzymes and MCF7 breast adenocarcinoma cells. Incubation of nobiletin in MCF7 cells produced one main metabolite (NM1) resulting from O-demethylation in either A or B rings of the flavone moiety. Among the three CYP1 isoforms, CYP1A1 exhibited the highest rate of metabolism of nobiletin in recombinant CYP microsomal enzymes. The intracellular CYP1-mediated bioconversion of the flavone was reduced in the presence of the CYP1A1 and CYP1B1-selective inhibitors α-napthoflavone and acacetin. In addition nobiletin induced CYP1 enzyme activity, CYP1A1 protein and CYP1B1 mRNA levels in MCF7 cells at a concentration dependent manner. MTT assays in MCF7 cells further revealed that nobiletin exhibited significantly lower IC50 (44 μM) compared to cells treated with nobiletin and CYP1A1 inhibitor (69 μM). FACS analysis demonstrated cell a cycle block at G1 phase that was attenuated in the presence of CYP1A1 inhibitor. Taken together the data suggests that the dietary flavonoid nobiletin induces its own metabolism and in turn enhances its cytostatic effect in MCF7 breast adenocarcinoma cells, via CYP1A1 and CYP1B1 upregulation.

  5. Metabolism of melatonin in the skin: Why is it important?

    PubMed

    Slominski, Andrzej T; Semak, Igor; Fischer, Tobias W; Kim, Tae-Kang; Kleszczyński, Konrad; Hardeland, Ruediger; Reiter, Russel J

    2016-09-13

    Melatonin is produced in almost all living taxa and is probably 2-3 billion years old. Its pleiotropic activities are related to its local concentration that is secondary to its local synthesis, delivery from distant sites and metabolic or non-enzymatic consumption. This consumption generates metabolites through indolic, kynuric and cytochrome P450 (CYP) mediated hydroxylations and O-demethylation or non-enzymatic processes, with potentially diverse phenotypic effects. While melatonin acts through receptor-dependent and receptor-independent mechanisms, receptors for melatonin metabolites remain to be identified, while their receptor-independent activities are well documented. The human skin with its main cellular components including malignant cells can both produce and rapidly metabolize melatonin in cell-type and context-dependent fashion. The predominant metabolism in human skin occurs through indolic, CYP-mediated and kynuric pathways with main metabolites represented by 6-hydroxymelatonin, N(1) -acetyl-N(2) -formyl-5-methoxykynuramine (AFMK), N(1) -acetyl-5-methoxykynuramine (AMK), 5-methoxytryptamine, 5-methoxytryptophol and 2-hydroxymelatonin. AFMK, 6-hydroxymelatonin, 2-hydroxymelatonin and probably 4-hydroxymelatonin can potentially be produced in epidermis through UVB-induced non-enzymatic melatonin transformation. The skin metabolites are also the same as those produced in lower organisms and plants indicating phylogenetic conservation across diverse species and adaptation by skin of the primordial defense mechanism. As melatonin and its metabolites counteract or buffer environmental stresses to maintain its homeostasis through broad-spectrum activities, both melatoninergic and degradative pathways must be precisely regulated, because the nature of phenotypic regulations will depend on local concentration of melatonin and its metabolites. These can be receptor-mediated or represent non-receptor regulatory mechanisms.

  6. Silicon surface biofunctionalization with dopaminergic tetrahydroisoquinoline derivatives

    NASA Astrophysics Data System (ADS)

    Lucena-Serrano, A.; Lucena-Serrano, C.; Contreras-Cáceres, R.; Díaz, A.; Valpuesta, M.; Cai, C.; López-Romero, J. M.

    2016-01-01

    In this work we grafted vinyl- and azido-terminated tetrahydroisoquinolines (compounds 1 and 2, respectively) onto Hsbnd Si(1 1 1) silicon wafers obtaining highly stable modified surfaces. A double bond was incorporated into the tetrahydroisoquinoline structure of 1 to be immobilized by a light induced hydrosilylation reaction on hydrogen-terminated Si(1 1 1). The best results were obtained employing a polar solvent (DMSO), rather than a non-polar solvent (toluene). The azide derivative 2 was grafted onto alkenyl-terminated silicon substrates with copper-catalyzed azide-alkyne cycloaddition (CuAAC). Atomic force microscopy (AFM), contact angle goniometry (CA) and X-ray photoemission spectroscopy (XPS) were used to demonstrate the incorporation of 1 and 2 into the surfaces, study the morphology of the modified surfaces and to calculate the yield of grafting and surface coverage. CA measurements showed the increase in the surface hydrophobicity when 1 or 2 were incorporated into the surface. Moreover, compounds 1 and 2 were prepared starting from 1-(p-nitrophenyl)tetrahydroisoquinoline 3 under smooth conditions and in good yields. The structures of 1 and 2 were designed with a reduced A-ring, two substituents at positions C-6 and C-7, an N-methyl group and a phenyl moiety at C-1 in order to provide a high affinity against dopaminergic receptors. Moreover, O-demethylation of 1 was carried out once it was adsorbed onto the surface by treatment with BBr3. The method presented constitutes a simple, easily reproducible and high yielding approach for grafting complex organic biomolecules with dopaminergic properties onto silicon surfaces.

  7. Ibogaine: complex pharmacokinetics, concerns for safety, and preliminary efficacy measures.

    PubMed

    Mash, D C; Kovera, C A; Pablo, J; Tyndale, R F; Ervin, F D; Williams, I C; Singleton, E G; Mayor, M

    2000-09-01

    Ibogaine is an indole alkaloid found in the roots of Tabernanthe Iboga (Apocynaceae family), a rain forest shrub that is native to western Africa. Ibogaine is used by indigenous peoples in low doses to combat fatigue, hunger and thirst, and in higher doses as a sacrament in religious rituals. Members of American and European addict self-help groups have claimed that ibogaine promotes long-term drug abstinence from addictive substances, including psychostimulants and opiates. Anecdotal reports attest that a single dose of ibogaine eliminates opiate withdrawal symptoms and reduces drug craving for extended periods of time. The purported efficacy of ibogaine for the treatment of drug dependence may be due in part to an active metabolite. The majority of ibogaine biotransformation proceeds via CYP2D6, including the O-demethylation of ibogaine to 12-hydroxyibogamine (noribogaine). Blood concentration-time effect profiles of ibogaine and noribogaine obtained for individual subjects after single oral dose administrations demonstrate complex pharmacokinetic profiles. Ibogaine has shown preliminary efficacy for opiate detoxification and for short-term stabilization of drug-dependent persons as they prepare to enter substance abuse treatment. We report here that ibogaine significantly decreased craving for cocaine and heroin during inpatient detoxification. Self-reports of depressive symptoms were also significantly lower after ibogaine treatment and at 30 days after program discharge. Because ibogaine is cleared rapidly from the blood, the beneficial aftereffects of the drug on craving and depressed mood may be related to the effects of noribogaine on the central nervous system.

  8. Isolation and characterization of two new homoacetogenic hydrogen-utilizing bacteria from the human intestinal tract that are closely related to Clostridium coccoides.

    PubMed Central

    Kamlage, B; Gruhl, B; Blaut, M

    1997-01-01

    Two gram-positive, strictly anoxic, coccoid- to rod-shaped strains of bacteria, Clostridium coccoides 1410 and C. coccoides 3110, were isolated from human feces on the typical homoacetogenic substrates formate plus H2 plus CO2 (strain 1410) and vanillate plus H2 plus CO2 (strain 3110) in the presence of 2-bromoethanesulfonate to inhibit methanogenesis. On the basis of 16S rRNA sequencing, DNA-DNA hybridization, and physiological and morphological parameters, both isolates are closely related to C. coccoides DSM 935T. The G+C contents of the DNA were 46.1 and 46.2 mol% for C. coccoides 1410 and C. coccoides 3110, respectively. Cytochromes could not be detected. Formate was degraded exclusively to acetate, whereas vanillate was O-demethylated, resulting in acetate and 3,4-dihydroxybenzoate, the latter being further decarboxylated to catechol. In the presence of organic substrates, H2 was cometabolized to acetate, but both strains failed to grow autotrophically. Lactose, lactulose, sorbitol, glucose, and various other carbohydrates supported growth as well. Untypical of homoacetogens, glucose and sorbitol were fermented not exclusively to acetate; instead, considerable amounts of succinate and D-lactate were produced. H2 was evolved from carbohydrates only in negligible traces. Acetogenesis from formate plus H2 plus CO2 or vanillate plus H2 plus CO2 was constitutive, whereas utilization of carbohydrates was inducible. Hydrogenase, CO dehydrogenase, formate dehydrogenase, and all of the tetrahydrofolic acid-dependent, C1 compound-converting enzymes of the acetyl-coenzyme A pathway of homoacetogenesis were present in cell extracts. PMID:9143110

  9. Degradation of Triazine-2-14C Metsulfuron–Methyl in Soil from an Oil Palm Plantation

    PubMed Central

    B. S., Ismail

    2015-01-01

    Triazine-2-14C metsulfuron–methyl is a selective, systemic sulfonylurea herbicide. Degradation studies in soils are essential for the evaluation of the persistence of pesticides and their breakdown products. The purpose of the present study was to investigate the degradation of triazine-2-14C metsulfuron–methyl in soil under laboratory conditions. A High Performance Liquid Chromatograph (HPLC) equipped with an UV detector and an on-line radio-chemical detector, plus a Supelco Discovery column (250 x 4.6 mm, 5 μm), and PRP–1 column (305 x 7.0 mm, 10 μm) was used for the HPLC analysis. The radioactivity was determined by a Liquid Scintillation Counter (LSC) in scintillation fluid. The soil used was both sterilized and non-sterilized in order to observe the involvement of soil microbes. The estimated DT50 and DT90 values of metsulfuron-methyl in a non-sterile system were observed to be 13 and 44 days, whereas in sterilized soil, the DT50 and DT90 were 31 and 70 days, respectively. The principal degradation product after 60 days was CO2. The higher cumulative amount of 14CO2 in 14C- triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound. The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine “ring-opened.” PMID:26437264

  10. Plant-derived leading compounds for chemotherapy of human immunodeficiency virus (HIV) infection.

    PubMed

    Vlietinck, A J; De Bruyne, T; Apers, S; Pieters, L A

    1998-03-01

    Many compounds of plant origin have been identified that inhibit different stages in the replication cycle of human immunodeficiency virus (HIV): 1) virus adsorption: chromone alkaloids (schumannificine), isoquinoline alkaloids (michellamines), sulphated polysaccharides and polyphenolics, flavonoids, coumarins (glycocoumarin, licopyranocoumarin) phenolics (caffeic acid derivatives, galloyl acid derivatives, catechinic acid derivatives), tannins and triterpenes (glycyrrhizin and analogues, soyasaponin and analogues); 2) virus-cell fusion: lectins (mannose- and N-acetylglucosamine-specific) and triterpenes (betulinic acid and analogues); 3) reverse transcription; alkaloids (benzophenanthridines, protoberberines, isoquinolines, quinolines), coumarins (calanolides and analogues), flavonoids, phloroglucinols, lactones (protolichesterinic acid), tannins, iridoids (fulvoplumierin) and triterpenes; 4) integration: coumarins (3-substituted-4-hydroxycoumarins), depsidones, O-caffeoyl derivatives, lignans (arctigenin and analogues) and phenolics (curcumin); 5) translation: single chain ribosome inactivating proteins (SCRIP's); 6) proteolytic cleavage (protease inhibition): saponins (ursolic and maslinic acids), xanthones (mangostin and analogues) and coumarins; 7) glycosylation: alkaloids including indolizidines (castanospermine and analogues), piperidines (1-deoxynojirimicin and analogues) and pyrrolizidines (australine and analogues); 8) assembly/release: naphthodianthrones (hypericin and pseudohypericin), photosensitisers (terthiophenes and furoisocoumarins) and phospholipids. The target of action of several anti-HIV substances including alkaloids (O-demethyl-buchenavianine, papaverine), polysaccharides (acemannan), lignans (intheriotherins, schisantherin), phenolics (gossypol, lignins, catechol dimers such as peltatols, naphthoquinones such as conocurvone) and saponins (celasdin B, Gleditsia and Gymnocladus saponins), has not been elucidated or does not fit in the

  11. Kinetics and selectivity of mechanism-based inhibition of guinea pig hepatic and pulmonary cytochrome P450 by N-benzyl-1-aminobenzotriazole and N-alpha-methylbenzyl-1-aminobenzotriazole.

    PubMed

    Sinal, C J; Bend, J R

    1996-09-01

    The time dependence for mechanism-based inactivation of cytochrome P450 (P450)-dependent 7-pentoxyresorufin O-depentylation (PROD), 7-ethoxyresorufin O-deethylation (EROD), and 7-methoxyresorufin O-demethylation (MROD) activities by N-benzyl-1-aminobenzotriazole (BBT) and N-alpha-methylbenzyl-1-aminobenzotriazole (alpha MB) was investigated in hepatic and pulmonary microsomes from phenobarbital-treated guinea pigs. In the presence of NADPH, both compounds inhibited P450-dependent catalytic activity in a time- and concentration-dependent manner. Inactivation of hepatic PROD activity was more rapid (t1/2 = 13.2 vs. 155 min) for 0.1 microM alpha MB when compared with equimolar BBT. On the other hand, hepatic EROD inactivation was more rapid (t1/2 = 8.1 vs. 11 min) with 0.1 microM BBT, compared with equimolar alpha MB. Inactivation of pulmonary PROD activity was the most rapid and potent, with an apparent half-life for inactivation of t1/2 = 0.94 and 32.2 min for 0.025 microM alpha MB and BBT, respectively. Incubation of hepatic microsomes for 45 min in the presence of NADPH and 10 microM BBT or alpha MB resulted in > 90% inhibition of PROD, EROD, and MROD activities. After washing by repeated sedimentation and resuspension, inhibition of PROD (78%; 93% for BBT and alpha MB, respectively), EROD (80% and 50%), and MROD (15% and 3%) activities was reversed to varying degrees. We conclude that BBT and alpha MB are rapidly metabolized to products that inhibit individual P450 isozymes by both mechanism-based (P4502B and P4501A1) and reversible (P4501A2) mechanisms. Of the two inhibitors, alpha MB is relatively more potent and selective for guinea pig lung P4502B isozyme(s).

  12. Isolation and quantitation of ecologically important phloroglucinols and other compounds from Eucalyptus jensenii.

    PubMed

    Sidana, Jasmeen; Foley, William J; Singh, Inder Pal

    2012-01-01

    Eucalyptus jensenii has not been explored for its phytoconstituents except for its essential oil although a formylated phloroglucinol compound jensenone has been the focus of several ecological studies. i) To optimise the extraction conditions for preparative scale isolation of jensenone and other secondary metabolites from leaves. (ii) To develop an RP-HPLC method for simultaneous determination of phloroglucinols and other compounds in Eucalyptus leaves. Jensenone and other compounds were isolated from acetone extract using VLC over TLC grade silica. HPLC quantitation of isolated compounds was undertaken on a C₁₈-column using acetonitrile-water (2% formic acid) gradient elution. Extraction conditions for isolation of jensenone were optimised and more than 99% pure jensenone was obtained in a yield of 2.1% from the dried leaves. Ten phloroglucinol compounds, including a new nuclear methylated phloroglucinol named 4-O-demethyl miniatone, and two triterpenoids were also isolated. A RP-HPLC method was developed for simultaneous quantitation of phloroglucinols and other compounds in different extracts of E. jensenii leaves. A total of 19 compounds reported from different species of Eucalyptus was separated by this method. The method described for isolation of jensenone is a simple, rapid and low-cost procedure amenable to the preparative scale. A new monomeric phloroglucinol compound was isolated and characterised from the acetone extract of E. jensenii leaves. The HPLC method developed can be applied successfully to different eucalypt matrices for precise and accurate determination of 19 secondary metabolites belonging to different chemical classes. Copyright © 2012 John Wiley & Sons, Ltd.

  13. Comparison of mibefradil and derivative NNC 55-0396 effects on behavior, cytochrome P450 activity, and tremor in mouse models of essential tremor.

    PubMed

    Quesada, Arnulfo; Bui, Peter H; Homanics, Gregg E; Hankinson, Oliver; Handforth, Adrian

    2011-05-20

    NNC 55-0396 [(1S,2S)-2-(2-(N-[(3-benzimidazol-2-yl)propyl]-N-methylamino)ethyl)-6-fluoro-1,2, 3,4-tetrahydro-1-isopropyl-2-naphtyl cyclopropanecarboxylate dihydrochloride], is a mibefradil derivative that retains potent in vitro T-type calcium channel antagonist efficacy. We compared the two compounds for behavioral toxicity, effects on cytochrome P450 activity, and efficacy against tremor in the γ-aminobutyric acid type A (GABAA) receptor subunit α1-null mouse, and the harmaline tremor model of essential tremor in wild-type mice. NNC 55-0396 was better tolerated than mibefradil in the horizontal wire test of sedation/motor function, with 3/6 failing at 300 and 30mg/kg respectively. To assess for a potential interaction with harmaline, mice were given the drugs, followed by harmaline or vehicle, and tested 30min later in the inverted wire grid test. Mibefradil exacerbated, whereas NNC 55-0396 ameliorated harmaline-induced test deficits. In mouse liver microsomes, NNC 55-0396 was a less potent inhibitor of harmaline O-demethylation than mibefradil (Ki: 0.95 and 0.29μM respectively), and also less potent at inhibiting testosterone 6-β-hydroxylation (Ki: 0.71 and 0.12μM respectively). In the GABAA α1-null model, NNC 55-0396 but not mibefradil, (each at 20mg/kg), suppressed tremor while NNC 55-0396 at 12.5mg/kg suppressed harmaline-induced tremor by half by 20-100min, whereas mibefradil at the same dose did not significantly affect tremor. In contrast to mibefradil, NNC 55-0396 is well tolerated and suppresses tremor, and exerts less cytochrome P450 inhibition. These results suggest potential clinical utility for NNC 55-0396 or similar derivatives as a T-type calcium antagonist. Published by Elsevier B.V.

  14. The metabolism and kinetics of doxazosin in man, mouse, rat and dog

    PubMed Central

    Kaye, B.; Cussans, N. J.; Faulkner, J. K.; Stopher, D. A.; Reid, J. L.

    1986-01-01

    1 The metabolic fate of doxazosin was investigated in man, mouse, rat and dog using 14C-labelled compound. Bioavailability and pharmacokinetic studies were also conducted with non-labelled drug, using a specific h.p.l.c. method. 2 Following both oral and intravenous administration, the major route of elimination of drug-related compounds was via the faeces for all species studied. Comparison of the oral and intravenous data show that doxazosin is completely absorbed in man, mouse and rat and is moderately well absorbed in dog. 3 The drug is extensively metabolized, e.g. only about 5% of the dose was excreted unchanged in man. Metabolism in man mainly involves 6- and 7- O-demethylation and 6′ and 7′-hydroxylation. These and some minor products were common to the mouse, rat or dog and man. 4 Plasma protein binding was high in all species studied, ranging from 95.3% in the rat to 98.3% in human patients. 5 Oral bioavailability is 60% in dog and approximately 50% in the rat, which is similar to the value of 63% reported for man at therapeutic doses. Mean plasma clearance values were 13 ml min-1 kg-1 (dogs), 30 ml min-1 kg-1 (rats) and 1.2 ml min-1 kg-1 (human subjects). Mean plasma half-life values were 5 h in dogs and 1.2 h in rats: a value of 9 h was reported for human volunteers (cf. 2.5 h for prazosin). The long plasma half-life of doxazosin provides the basis for once-daily dosing. PMID:2939865

  15. Effect of azole antifungals ketoconazole and fluconazole on the pharmacokinetics of dexloxiglumide.

    PubMed

    Jakate, Abhijeet S; Roy, Partha; Patel, Alpita; Abramowitz, Wattanaporn; Persiani, Stefano; Wangsa, Julie; Kapil, Ram

    2005-11-01

    Dexloxiglumide is a new CCK(1) receptor antagonist under investigation for treatment of functional gastrointestinal disorders and is metabolized by CYP3A4 and CYP2C9. The objectives of these two separate randomized, two-period, two-treatment crossover studies were to investigate the effects of steady-state ketoconazole, a model CYP3A4 inhibitor (Study 1), and steady-state fluconazole, a model CYP2C9 inhibitor (Study 2), on the pharmacokinetics of dexloxiglumide in healthy subjects. Plasma samples were analysed for dexloxiglumide and its primary metabolites: O-demethyl dexloxiglumide (ODM; Study 1 and 2) and dexloxiglumide carboxylic acid (DCA; Study 2). Following ketoconazole coadministration, dexloxiglumide C(max) increased by 32% (90% confidence intervals (CI) 112-154), with unchanged ODM C(max); AUC of dexloxiglumide and ODM increased by 36% (90% CI 124-140 and 128-142, respectively). No changes were observed in dexloxiglumide or ODM t((1/2)). Fluconazole coadministration caused a 77% increase (90% CI 154-204) in dexloxiglumide C(max), no change in ODM C(max) and a 32% decrease (90% CI 62-75) in DCA C(max). Fluconazole coadministration resulted in a 2.5-fold increase (90% CI 235-267) in dexloxiglumide AUC, 40% increase (90% CI 136-156) in ODM AUC and an 18% decrease (90% CI 82-94) in DCA AUC. The t((1/2)) of all three analytes increased by approximately 2-fold with fluconazole coadministration (P-value < 0.05). Ketoconazole caused a minimal increase while fluconazole caused a moderate increase in dexloxiglumide systemic exposure with no change in the adverse event profile of dexloxiglumide.

  16. In vitro metabolism of a novel antithrombotic compound, S002-333, and its enantiomers: quantitative cytochrome P450 phenotyping, metabolic profiling and enzyme kinetic studies.

    PubMed

    Saxena, Amrita; Jain, Girish K; Siddiqui, Hefazat H; Bhunia, Shom S; Saxena, Anil K; Gayen, Jiaur R

    2014-04-01

    1. S002-333, (2-(4'-methoxy-benzenesulfonyl)-2,3,4,9-tetrahydro-1H-pyrido (3,4-b) indole-3-carboxylic acid amide) is a novel potent antithrombotic molecule currently under development phase. It is the racemic mixture of two enantiomers, namely S004-1032 (R-form) and S007-1558 (S-form). 2. The contribution of five major isoenzymes, namely CYP2B6, 2C9, 2C19, 2D6 and 3A4 was quantified using recombinant P450s in the phase-I metabolism through relative activity factor approach. CYP2C19 was found to be the major contributor for S002-333 and S007-1558, while CYP3A4 showed greater involvement in S004-1032 metabolism. Chemical inhibition and immunoinhibition studies reconfirmed the results in human liver microsomes (HLM). 3. Four major phase-I metabolites of S002-333; M-1 and M-3 (oxidative), M-2 (O-demethylated) and M-4 (dehydrogenated) were characterized in HLM. These metabolites constituted 11.2, 11.3 and 21.5% of the parent in comparison with the net phase-I metabolism of 29.9, 31.4 and 38.3% of S002-333, S004-1032 and S007-1558, respectively. 4. Among CYP2C9, 2C19 and 3A4, the relative contribution of CYP2C9 was found to be maximum during M-1 through M-4 formation. Enzyme kinetic analysis for detected metabolites indicated that M-1 to M-3 followed classical hyperbolic kinetics, whereas M-4 showed evidence of autoactivation. In conclusion, the results suggest prominent role of CYP2C9, 2C19 and 3A4 isoforms for enantioselective disposition of S002-333 in vitro.

  17. Isolation, identification, optimization, and metabolite profiling of Streptomyces sparsus VSM-30.

    PubMed

    Managamuri, Ushakiranmayi; Vijayalakshmi, Muvva; Ganduri, V S Rama Krishna; Rajulapati, Satish Babu; Bonigala, Bodaiah; Kalyani, B S; Poda, Sudhakar

    2017-07-01

    Deep sea sediment samples of Bay of Bengal (Visakhapatnam) have been analyzed for actinomycetes as an elite source to screen for the production of bioactive metabolites. The actinomycetes strain VSM-30 has an exciting bioactivity profile and was isolated during our systemic screening of marine actinomycetes. It was identified as Streptomyces sparsus based on morphological, physiological, biochemical, and molecular approaches. Response surface methodology regression analysis was carried out to fit the experimental data of each response by the second-order polynomial. The results have proven right interaction among process variables at optimized values of incubation time at 12 days, pH at 8, temperature at 30 °C, concentrations of starch at 1%, and tryptone at 1% and the data have been adequately fitted into the second-order polynomial models. Under these conditions, the responses (zones of inhibition) of plant pathogenic fungi Aspergillus niger, Aspergillus flavus, Fusarium oxysporum, Fusarium solani, and Penicillium citrinum were also matched with experimental and predicted results. Chemotypic analysis of ethyl acetate extract of the strain was done using LC-Q-TOF-MS revealed the presence of bioactive compounds including tryptophan dehydrobutyrine diketopiperazine, maculosin, 7-o-demethyl albocycline, albocycline M-2, and 7-o-demethoxy-7-oxo albocycline in a negative ion mode. The ethyl acetate extract of actinobacterium has been subjected to gas chromatography and mass spectroscopy (GC-MS) revealed the presence of diverse compounds such as dotriacontane, tetracosane 11-decyl-, diheptyl phthalate, 1-hexadecanesulfonyl chloride, L-alanyl-L-tryptophan, phthalic acid ethyl pentyl ester, 4-trifluoroacetoxyhexadecane, and 1H-imidazole 4,5-dihydro-2,4-dimethyl. Hence, the ethyl acetate extract of Streptomyces sparsus VSM-30 may have antibacterial, antifungal, and antioxidant activities due to the presence of secondary metabolites in ethyl acetate extract. The study

  18. Isoxanthohumol--Biologically active hop flavonoid.

    PubMed

    Żołnierczyk, Anna Katarzyna; Mączka, Wanda Krystyna; Grabarczyk, Małgorzata; Wińska, Katarzyna; Woźniak, Edyta; Anioł, Mirosław

    2015-06-01

    Isoxanthohumol (IXN), apart from xanthohumol (XN) and 8-prenylnaringenin (8PN), is one of the most important prenylflavonoids found in hops. Another natural source of this compound is a shrub Sophora flavescens, used in traditional Chinese medicine. Main dietary source of IXN is beer, and the compound is produced from XN during wort boiling. In the human body, the compound is O-demethylated to 8PN, the strongest known phytoestrogen. This process takes place in the liver and in the intestine, where it is mediated by local microflora. It has been reported in some studies that even though beer contains small amounts of hops and its preparations, these compounds may affect the functioning of the human body. IXN exhibits an antiproliferative activity against human cell lines typical for breast cancer (MCF-7), ovarian cancer (A-2780), prostate cancer (DU145 and PC-3), and colon cancer (HT-29 and SW620) cells. It strongly inhibits the activation of the following carcinogens: 2-amino-3-methylimidazol-[4,5-f]quinoline and aflatoxin B1 (AFB1) via human cytochrome P450 (CYP1A2). It also inhibits the production of prostate specific antigen (PSA). IXN significantly reduces the expression of transforming growth factor-β (TGF-β) in the case of invasive breast cancer MDA-MB-231. It interferes with JAK/STAT signaling pathway and inhibits the expression of pro1inflammatory genes in the monoblastic leukemia cell line (MonoMac6). It activates apoptosis in human umbilical vein endothelial cells (HUVEC) and human aortic smooth muscle cells (HASMCs). In addition, IXN shows an antiviral activity towards herpes viruses (HSV1 and HSV2) and bovine viral diarrhea virus (BVDV).

  19. A model for human cytochrome P450 2D6 based on homology modeling and NMR studies of substrate binding.

    PubMed

    Modi, S; Paine, M J; Sutcliffe, M J; Lian, L Y; Primrose, W U; Wolf, C R; Roberts, G C

    1996-04-09

    The cytochrome P450 responsible for the debrisoquine/sparteine polymorphism (P450 2D6) has been produced in large quantities by expression of a modified cDNA in baculovirus. A polyhistidine extension was incorporated at the C-terminus of the expressed protein, which, after purification of the protein on a nickel-agarose column, could be removed proteolytically by treatment with thrombin. Purified yields of P450 2D6 were 2.4 mg from 700 mL of cell culture. The protein had a greater than 90% heme content and was fully active, having no residual absorbance at 420 nm in the reduced CO complex. The quantities produced allowed direct study of the interaction of the substrate codeine with the enzyme by paramagnetic relaxation effects on the NMR spectrum of the substrate. Distances between the heme iron atom and substrate protons were calculated from these experiments, and the orientation of the substrate in the binding pocket was determined. This showed that codeine was bound with the methoxy group of the molecule closest to the heme iron (iron-methyl proton distance of 3.1 +/- 0.1 A), consistent with the observed O-demethylation to morphine. A model of the complex Of P450 2D6 with codeine was built from a multiple sequence and structure alignment of the known crystal structures for P450s, incorporating the experimental constraints derived from the NMR studies. This showed that the overall fold Of P450 2D6 is more similar to that of P450 BM3 than to either P450 cam or P450 terp. Codeine binds to P450 2D6 so that the methoxy group is directly above the A ring of the heme, while the basic nitrogen interacts with the carboxylate of aspartate 301.

  20. Metabolism of the new psychoactive substances N,N-diallyltryptamine (DALT) and 5-methoxy-DALT and their detectability in urine by GC-MS, LC-MSn, and LC-HR-MS-MS.

    PubMed

    Michely, Julian A; Helfer, Andreas G; Brandt, Simon D; Meyer, Markus R; Maurer, Hans H

    2015-10-01

    N,N-Diallyltryptamine (DALT) and