Sample records for propafenone

  1. Effect of steroid eluting versus conventional electrodes on propafenone induced rise in chronic ventricular pacing threshold.

    PubMed

    Cornacchia, D; Fabbri, M; Maresta, A; Nigro, P; Sorrentino, F; Puglisi, A; Ricci, R; Peraldo, C; Fazzari, M; Pistis, G

    1993-12-01

    The aim of this study was to evaluate chronic ventricular pacing threshold increase after oral propafenone therapy. Eighty-three patients affected by advanced atrioventricular block and sick sinus syndrome were studied at least 3 months after pacemaker implantation, before and after oral propafenone therapy (450-900 mg/day based on body weight). The patients were subdivided into three groups according to the type of unipolar electrode that was implanted: group I (41 patients) Medtronic CapSure 4003, group II (30 patients) Medtronic Target Tip 4011, and group III (12 patients) Osypka Vy screw-in lead. In all cases a Medtronic unipolar pacemaker was implanted: 30 Minix, 23 Activitrax, 14 Elite, 12 Legend, and 4 Pasys. Propafenone blood level was measured in 75 patients 3-5 hours after propafenone administration. The pacing autothreshold was measured at 0.8 V, 1.6 V, and 2.5 V by reducing pulse width. At the three different outputs before and after propafenone, threshold increments were significantly lower in group I in comparison with group II and group III (propafenone ranging from < 0.001 to < 0.05). No significant difference was found in pacing impedance or in propafenone plasma concentration in the three groups. Strength-duration curves were drawn for each group at baseline and after propafenone administration. Before propafenone, in group I, the knee was markedly shifted to the left and downward as compared to the classic curve, so that the steep part was predominant; in group II and group III this shift was progressively less evident.(ABSTRACT TRUNCATED AT 250 WORDS)

  2. Propafenone effects on the stable structures of Aβ16-22 system

    NASA Astrophysics Data System (ADS)

    Tran, Linh; Ngo, Son Tung; Nguyen, Minh Tho

    2018-03-01

    An extensive replica exchange molecular dynamics (REMD) simulation was performed to investigate the progress patterns of the molecular interactions of propafenone and Aβ16-22 system. Distinct conformational equilibrium of Aβ16-22 system with and without propafenone was analyzed in detail. Propafenone can act to prevent the Alzheimer's disease (AD) by significantly inhibiting Aβ oligomerization. Our calculated results provide insights into the inhibition mechanism of propafenone on the oligomerization process to form Aβ16-22 peptide aggregation. These findings are valuable for the development of therapeutic drugs in the AD early stage.

  3. Preparative enantioseparation of propafenone by counter-current chromatography using di-n-butyl L-tartrate combined with boric acid as the chiral selector.

    PubMed

    Tong, Shengqiang; Shen, Mangmang; Zheng, Ye; Chu, Chu; Li, Xing-Nuo; Yan, Jizhong

    2013-09-01

    This paper extends the research of the utilization of borate coordination complexes in chiral separation by counter-current chromatography (CCC). Racemic propafenone was successfully enantioseparated by CCC with di-n-butyl l-tartrate combined with boric acid as the chiral selector. The two-phase solvent system was composed of chloroform/ 0.05 mol/L acetate buffer pH 3.4 containing 0.10 mol/L boric acid (1:1, v/v), in which 0.10 mol/L di-n-butyl l-tartrate was added in the organic phase. The influence of factors in the enantioseparation of propafenone were investigated and optimized. A total of 92 mg of racemic propafenone was completely enantioseparated using high-speed CCC in a single run, yielding 40-42 mg of (R)- and (S)-propafenone enantiomers with an HPLC purity over 90-95%. The recovery for propafenone enantiomers from fractions of CCC was in the range of 85-90%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Bioavailability of an extemporaneous suspension of propafenone made from tablets.

    PubMed

    Olguín, Hugo Juárez; Pérez, Carmen Flores; Pérez, Janett Flores; Mendiola, Blanca Ramírez; Portugal, Miriam Carrasco; Chávez, Jesús Bobadilla

    2006-07-01

    Propafenone is an effective antiarrhythmic agent used in children, while in Mexico no specific formulation for children is available, which causes errors in adequate dosage. The aim of this study was to determine the bioavailability of a suspension prepared extemporaneously using commercial tablets of propafenone. The bioavailability was determined in two groups of rabbits (n = 8): the first group received a single intravenous dose of 2 mg/kg of propafenone; the second was orally administered an extemporaneous suspension of propafenone prepared from commercial tablets. Blood samples were drawn at several times during the next 24 h and analysed by HPLC to determine drug levels. The extemporaneous suspension was tested previously with satisfactory results regarding physicochemical and microbiologic stability. The area under the curve (AUC) for the i.v. route was 5600.6 ng/ml.h and for oral administration the AUC was 3327.6 ng/ml.h. The bioavailability was calculated at 59.41%. These results are consistent with previous reports for solid dosage forms. The propafenone suspension prepared extemporaneously using commercial tablets is bioavailable using an animal model; nevertheless, it is necessary to carry out human studies either in volunteers or in patients to confirm these results.

  5. Pharmacokinetics of propafenone hydrochloride sustained-release capsules in male beagle dogs.

    PubMed

    Pan, Liping; Qian, Yafang; Cheng, Minlu; Gu, Pan; He, Yanna; Xu, Xiaowen; Ding, Li

    2015-01-01

    This paper describes the development and validation of a liquid chromatography-mass spectrometric assay for propafenone and its application to a pharmacokinetic study of propafenone administered as a new propafenone hydrochloride sustained-release capsule (SR-test), as an instant-release tablet (IR-reference) and as the market leader sustained-release capsule (Rythmol, SR-reference) in male beagle dogs (n=8). In Study A comparing SR-test with IR-reference in a crossover design T max and t 1/2 of propafenone for SR-test were significantly higher than those for IR-reference while C max and AUC were lower demonstrating the sustained release properties of the new formulation. In Study B comparing SR-test with SR-reference the observed C max and AUC of propafenone for SR-test (124.5±140.0 ng/mL and 612.0±699.2 ng·h/mL, respectively) were higher than for SR-reference (78.52±72.92 ng/mL and 423.6±431.6 ng·h/mL, respectively) although the differences were not significant. Overall, the new formulation has as good if not better sustained release characteristics to the market leader formulation.

  6. Extemporaneous suspension of propafenone: attending lack of pediatric formulations in Mexico.

    PubMed

    Juárez Olguín, Hugo; Flores Pérez, Carmen; Ramírez Mendiola, Blanca; Coria Jiménez, Rafael; Sandoval Ramírez, Eunice; Flores Pérez, Janett

    2008-11-01

    Physicians have frequently encountered difficulties when prescribing drugs not available in doses suitable for pediatric age groups. Furthermore, children have difficulty swallowing tablets. This study aimed to determine the stability of an oral propafenone suspension made from commercial tablets with a syrup vehicle and to establish its reliable use with children. An extemporaneous suspension of propafenone 1.5 mg/ml was prepared with commercial tablets. Its physicochemical and microbiologic stability was established by constant monitoring during 90 days at room temperature (15 +/- 5 degrees C) and at refrigeration (3-5 degrees C). Plasma levels of propafenona were measured in two children with supraventricular tachycardia at steady state. The suspension was stable, maintaining its original physicochemical and microbiologic properties. Moreover, no apparent changes in color or odor were observed. Plasma levels of propafenone in patients demonstrated therapeutic concentrations after they had taken the suspension, with no unwanted outcome. The conservation of both physicochemical and microbiologic stability of the suspension represents an option for the administration of propafenone to children.

  7. Propafenone

    MedlinePlus

    ... arrhythmia (irregular heartbeat) and to maintain a normal heart rate. Propafenone is in a class of medications called antiarrhythmics. It works by acting on the heart muscle to improve the heart's rhythm.

  8. [Therapy of arrhythmia induced by myocardial ischemia. Association of L-carnitine, propafenone and mexiletine].

    PubMed

    Mondillo, S; Faglia, S; D'Aprile, N; Mangiacotti, L; Campolo, M A; Agricola, E; Palazzuoli, V

    1995-12-01

    To assess the anti-arrythmic effect of L-carnitina, propafenone and mexiletine, we tested the drugs in 50 patients with effort angina and ventricular ectopic beats (VEB). The patients were randomized in 5 groups: Group A: was treated with oral L-carnitine at the dose of 2 g x 3 for two weeks. Group B: oral propafenone at the dose of 300 mg x 3 for two weeks. Group C: as group B+L-carnitine+g x 3 at the second weeks. Group D: oral mexiletine at the dose of 200 mg x 3 for two weeks. Group E: as group D+L-carnitine 2 gr x 3 at the second week. After 7 and 14 days of treatment, in all patients an Holter examination was performed. Our results show that L-carnitine exerts a significant reduction of the VEB and its administration potentiates the anti-arrythmic effect of propafenone and mexiletine.

  9. Preparation and evaluation of unitary doses of propafenone used in children with supraventricular tachycardia: a pilot study.

    PubMed

    Flores Pérez, J; Ramírez Mendiola, B; Flores Pérez, C; García Álvarez, R; Juárez Olguín, H

    2013-01-01

    The aim was to prepare and evaluate unitary doses of propafenone (UDP) used in children with supraventricular tachycardia. UDP were prepared from four brands of tablets at doses of propafenone, 11, 25 and 90 mg, used in the Cardiology Service of this Institute. The stability of doses was determined at 20±5°C and 40°C for up to day 30. Besides, a weight variation test was performed. Plasma levels of propafenone were determined at steady state in 3 children diagnosed with supraventricular tachycardia under treatment with UDP. Concentrations of drug in blood were measured using a high pressure liquid chromatography method, previously validated. The stability of UDP, showed no significant statistical differences (p > 0.05) between doses or brands up to day 30, at both temperatures. The coefficient of variation from the weight variation was less than 6%. The plasma levels of propafenone at steady state were: patient 1, 31.57 ng/ml; patient 2, 226.46 ng/ml; and patient 3, 221.29 ng/ml. The actual administered dose for the patients could vary up to 6%, and doses prepared from different brands of tablets remain stables for up to day 30 at both temperatures. UDP is a temporal, safe and alternative option when pediatrics formulation of this drug is lacking.

  10. Overlapping Binding Sites of Structurally Different Antiarrhythmics Flecainide and Propafenone in the Subunit Interface of Potassium Channel Kv2.1*

    PubMed Central

    Madeja, Michael; Steffen, Wibke; Mesic, Ivana; Garic, Bojan; Zhorov, Boris S.

    2010-01-01

    Kv2.1 channels, which are expressed in brain, heart, pancreas, and other organs and tissues, are important targets for drug design. Flecainide and propafenone are known to block Kv2.1 channels more potently than other Kv channels. Here, we sought to explore structural determinants of this selectivity. We demonstrated that flecainide reduced the K+ currents through Kv2.1 channels expressed in Xenopus laevis oocytes in a voltage- and time-dependent manner. By systematically exchanging various segments of Kv2.1 with those from Kv1.2, we determined flecainide-sensing residues in the P-helix and inner helix S6. These residues are not exposed to the inner pore, a conventional binding region of open channel blockers. The flecainide-sensing residues also contribute to propafenone binding, suggesting overlapping receptors for the drugs. Indeed, propafenone and flecainide compete for binding in Kv2.1. We further used Monte Carlo-energy minimizations to map the receptors of the drugs. Flecainide docking in the Kv1.2-based homology model of Kv2.1 predicts the ligand ammonium group in the central cavity and the benzamide moiety in a niche between S6 and the P-helix. Propafenone also binds in the niche. Its carbonyl group accepts an H-bond from the P-helix, the amino group donates an H-bond to the P-loop turn, whereas the propyl group protrudes in the pore and blocks the access to the selectivity filter. Thus, besides the binding region in the central cavity, certain K+ channel ligands can expand in the subunit interface whose residues are less conserved between K+ channels and hence may be targets for design of highly desirable subtype-specific K+ channel drugs. PMID:20709754

  11. Lead optimization of antimalarial propafenone analogues.

    PubMed

    Lowes, David; Pradhan, Anupam; Iyer, Lalitha V; Parman, Toufan; Gow, Jason; Zhu, Fangyi; Furimsky, Anna; Lemoff, Andrew; Guiguemde, W Armand; Sigal, Martina; Clark, Julie A; Wilson, Emily; Tang, Liang; Connelly, Michele C; Derisi, Joseph L; Kyle, Dennis E; Mirsalis, Jon; Guy, R Kiplin

    2012-07-12

    Previously reported studies identified analogues of propafenone that had potent antimalarial activity, reduced cardiac ion channel activity, and properties that suggested the potential for clinical development for malaria. Careful examination of the bioavailability, pharmacokinetics, toxicology, and efficacy of this series of compounds using rodent models revealed orally bioavailable compounds that are nontoxic and suppress parasitemia in vivo. Although these compounds possess potential for further preclinical development, they also carry some significant challenges.

  12. Lead Optimization of Anti-Malarial Propafenone Analogs

    PubMed Central

    Lowes, David; Pradhan, Anupam; Iyer, Lalitha V.; Parman, Toufan; Gow, Jason; Zhu, Fangyi; Furimsky, Anna; Lemoff, Andrew; Guiguemde, W. Armand; Sigal, Martina; Clark, Julie A.; Wilson, Emily; Tang, Liang; Connelly, Michele C.; DeRisi, Joseph L.; Kyle, Dennis E.; Mirsalis, Jon; Guy, R. Kiplin

    2015-01-01

    Previously reported studies identified analogs of propafenone that had potent antimalarial activity, reduced cardiac ion channel activity, and properties that suggested the potential for clinical development for malaria. Careful examination of the bioavailability, pharmacokinetics, toxicology, and efficacy of this series of compounds using rodent models revealed orally bioavailable compounds that are non-toxic and suppress parasitemia in vivo. Although these compounds possess potential for further preclinical development, they also carry some significant challenges. PMID:22708838

  13. Comparative pharmacokinetics between a microdose and therapeutic dose for clarithromycin, sumatriptan, propafenone, paracetamol (acetaminophen), and phenobarbital in human volunteers.

    PubMed

    Lappin, Graham; Shishikura, Yoko; Jochemsen, Roeline; Weaver, Richard John; Gesson, Charlotte; Brian Houston, J; Oosterhuis, Berend; Bjerrum, Ole J; Grynkiewicz, Grzegorz; Alder, Jane; Rowland, Malcolm; Garner, Colin

    2011-06-14

    A clinical study was conducted to assess the ability of a microdose (100 μg) to predict the human pharmacokinetics (PK) following a therapeutic dose of clarithromycin, sumatriptan, propafenone, paracetamol (acetaminophen) and phenobarbital, both within the study and by reference to the existing literature on these compounds and to explore the source of any nonlinearity if seen. For each drug, 6 healthy male volunteers were dosed with 100 μg (14)C-labelled compound. For clarithromycin, sumatriptan, and propafenone this labelled dose was administered alone, i.e. as a microdose, orally and intravenously (iv) and as an iv tracer dose concomitantly with an oral non-labelled therapeutic dose, in a 3-way cross over design. The oral therapeutic doses were 250, 50, and 150 mg, respectively. Paracetamol was given as the labelled microdose orally and iv using a 2-way cross over design, whereas phenobarbital was given only as the microdose orally. Plasma concentrations of total (14)C and parent drug were measured using accelerator mass spectrometry (AMS) or HPLC followed by AMS. Plasma concentrations following non-(14)C-labelled oral therapeutic doses were measured using either HPLC-electrochemical detection (clarithromycin) or HPLC-UV (sumatriptan, propafenone). For all five drugs an oral microdose predicted reasonably well the PK, including the shape of the plasma profile, following an oral therapeutic dose. For clarithromycin, sumatriptan, and propafenone, one parameter, oral bioavailability, was marginally outside of the normally acceptable 2-fold prediction interval around the mean therapeutic dose value. For clarithromycin, sumatriptan and propafenone, data obtained from an oral and iv microdose were compared within the same cohort of subjects used in the study, as well as those reported in the literature. For paracetamol (oral and iv) and phenobarbital (oral), microdose data were compared with those reported in the literature only. Where 100 μg iv (14)C-doses were given alone and with an oral non-labelled therapeutic dose, excellent accord between the PK parameters was observed indicating that the disposition kinetics of the drugs tested were unaffected by the presence of therapeutic concentrations. This observation implies that any deviation from linearity following the oral therapeutic doses occurs during the absorption process. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. A sensitive quantitative assay for the determination of propafenone and two metabolites, 5-hydroxypropafenone and N-depropylpropafenone, in human K2EDTA plasma using LC-MS/MS with ESI operated in positive mode.

    PubMed

    Patel, Harilal; Ghoghari, Ashok; Bhatt, Chandrakant; Shah, Shaival; Jha, Anilkumar; Desai, Nirmal; Srinivas, Nuggehally R

    2017-10-01

    Propafenone is a potent antiarrhythmic agent; clinically propafenone has been used for a number of cardiac arrhythmias because it possesses multiple modes of action, via beta adrenergic receptor blockade and calcium antagonistic activity. Propafenone (PPF) exhibits extensive saturable presystemic biotransformation (first-pass effect) resulting in two active metabolites: 5-hydroxypropafenone (5-OH PPF) formed by CYP2D6 and N-depropylpropafenone (NDP) formed by both CYP3A4 and CYP1A2 enzymes. A specific and sensitive LC-MS/MS method was developed and validated for quantitation of PPF, 5-OH PPF and NDP using turboion spray in a positive ion mode. A solid-phase extraction was employed for the extraction from human plasma. Chromatographic separation of analytes was achieved using an ACE-5 C 8 (50 × 4.6 mm) column with a gradient mobile phase comprising ammonium acetate containing 0.01% TFA in purified water and acetonitrile. The retention times achieved were 1.36, 1.23, 1.24 min and 1.34 min for PPF, 5-OH PPF, NDP and IS (carbamazepine), respectively. Quantitation was performed by monitoring multiple reaction monitoring transition pairs of m/z 342.30 to m/z 116.20, m/z 358.30 to m/z 116.20, m/z 300.30 to m/z 74.20 and m/z 237.20 to m/z 194.10, respectively. The developed method was validated for various parameters. The calibration curves of PPF and 5-OH PPF showed linearity from 1 to 500 ng/mL, with a lower limit of quantitation of 1.0 ng/mL and for NDP linearity from 0.1 to 25 ng/mL with a lower limit of quantitation of 0.1 ng/mL. The bias and precision for intra- and-inter batch assays were <10 and 5%, respectively. The developed assay was used to evaluate pharmacokinetic properties of propafenone and its major metabolites in healthy human subjects. Copyright © 2017 John Wiley & Sons, Ltd.

  15. Structural basis of drugs that increase cardiac inward rectifier Kir2.1 currents.

    PubMed

    Gómez, Ricardo; Caballero, Ricardo; Barana, Adriana; Amorós, Irene; De Palm, Sue-Haida; Matamoros, Marcos; Núñez, Mercedes; Pérez-Hernández, Marta; Iriepa, Isabel; Tamargo, Juan; Delpón, Eva

    2014-11-01

    We hypothesize that some drugs, besides flecainide, increase the inward rectifier current (IK1) generated by Kir2.1 homotetramers (IKir2.1) and thus, exhibit pro- and/or antiarrhythmic effects particularly at the ventricular level. To test this hypothesis, we analysed the effects of propafenone, atenolol, dronedarone, and timolol on Kir2.x channels. Currents were recorded with the patch-clamp technique using whole-cell, inside-out, and cell-attached configurations. Propafenone (0.1 nM-1 µM) did not modify either IK1 recorded in human right atrial myocytes or the current generated by homo- or heterotetramers of Kir2.2 and 2.3 channels recorded in transiently transfected Chinese hamster ovary cells. On the other hand, propafenone increased IKir2.1 (EC50 = 12.0 ± 3.0 nM) as a consequence of its interaction with Cys311, an effect which decreased inward rectification of the current. Propafenone significantly increased mean open time and opening frequency at all the voltages tested, resulting in a significant increase of the mean open probability of the channel. Timolol, which interacted with Cys311, was also able to increase IKir2.1. On the contrary, neither atenolol nor dronedarone modified IKir2.1. Molecular modelling of the Kir2.1-drugs interaction allowed identification of the pharmacophore of drugs that increase IKir2.1. Kir2.1 channels exhibit a binding site determined by Cys311 that is responsible for drug-induced IKir2.1 increase. Drug binding decreases channel affinity for polyamines and current rectification, and can be a mechanism of drug-induced pro- and antiarrhythmic effects not considered until now. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  16. Pharmacological conversion of recent-onset atrial fibrillation: a systematic review.

    PubMed

    Heldal, Magnus; Atar, Dan

    2013-02-01

    Recent-onset (duration ≤ 1 week) atrial fibrillation (AF) has a high rate of spontaneous conversion to sinus rhythm (SR); still anti-arrhythmic drugs (AAD) are given for conversion purposes. We assessed the effect of AADs by reviewing the literature regarding conversion rates of available drugs in a systematic manner. PubMed searches were performed using the terms "drug name", "atrial fibrillation", and "clinical study/RCT", and a list of 1302 titles was generated. These titles, including abstracts or complete papers when needed, were reviewed for recent-onset of AF, the use of a control group, and the endpoint of SR within 24 hours. Postoperative and intensive care settings were excluded. Five AADs were demonstrated to have an effect, and these were Amiodarone, Ibutilide (only one study and risk of torsade de pointes), Flecainide and Propafenone (only to be used in patients without structural heart disease) and Vernakalant. The time taken for conversion differed markedly; Vernakalant converted after 10 minutes, while Amiodarone converted only after 24 hours; Propafenone and Flecainide had conversion times in-between. For a rapid response in a broad group of patients, Vernakalant appears to be a reasonable first choice, while Flecainide and Propafenone can be used in patients without structural heart disease.

  17. Assessing the Risk for Peripheral Neuropathy in Patients Treated With Dronedarone Compared With That in Other Antiarrhythmics.

    PubMed

    Wu, Chuntao; Tcherny-Lessenot, Stephanie; Dai, Wanju; Wang, Yunxun; Kechemir, Hayet; Gandhi, Sampada; Lin, Stephen; Juhaeri, Juhaeri

    2018-03-01

    There are few data on the risk for peripheral neuropathy associated with dronedarone, a newer antiarrhythmic medicine. The objective of this study was to assess whether dronedarone is potentially associated with an increased risk for peripheral neuropathy compared with other antiarrhythmics, including amiodarone, sotalol, flecainide, and propafenone. The MarketScan database was used for identifying patients who were at least 18 years of age, had atrial fibrillation or flutter, and had not been diagnosed with peripheral neuropathy in the 180-day period prior to or on the date of the first prescription of an antiarrhythmic between July 20, 2009, and December 31, 2011. Peripheral neuropathy that occurred during the treatment period for a study drug was ascertained using ICD-9-CM diagnostic codes. For each antiarrhythmic, the incidence rate of peripheral neuropathy was calculated. The adjusted hazard ratio (aHR) for peripheral neuropathy for dronedarone compared with another antiarrhythmic was obtained, with control for age, sex, diabetes mellitus status, and the presence of other comorbidities. The study population included 106,933 patients treated with dronedarone (n = 12,989), amiodarone (n = 45,173), sotalol (n = 22,036), flecainide (n = 14,244), or propafenone (n = 12,491). The incidence rates (per 1000 person-years) of peripheral neuropathy were 1.33 for dronedarone, 2.38 for amiodarone, 1.20 for sotalol, 1.08 for flecainide, and 1.97 for propafenone. The aHRs for peripheral neuropathy for dronedarone relative to other drugs ranged from 0.53 (95% CI, 0.21-1.34) compared with propafenone, to 0.94 (95% CI, 0.38-2.30) compared with sotalol. A new-user analysis showed similar results. The risks for peripheral neuropathy were not significantly different between dronedarone and other antiarrhythmics. Copyright © 2018 Elsevier HS Journals, Inc. All rights reserved.

  18. Grape

    MedlinePlus

    ... fruit, skin, leaves and seed of the grape plant are used as medicine. Grape seeds are by- ... haloperidol (Haldol), imipramine (Tofranil), mexiletine (Mexitil), mirtazapine (Remeron), naproxen (Naprosyn), nortriptyline (Pamelor), olanzapine (Zyprexa), ondansetron (Zofran), propafenone ( ...

  19. Application of chimeric mice with humanized liver for study of human-specific drug metabolism.

    PubMed

    Bateman, Thomas J; Reddy, Vijay G B; Kakuni, Masakazu; Morikawa, Yoshio; Kumar, Sanjeev

    2014-06-01

    Human-specific or disproportionately abundant human metabolites of drug candidates that are not adequately formed and qualified in preclinical safety assessment species pose an important drug development challenge. Furthermore, the overall metabolic profile of drug candidates in humans is an important determinant of their drug-drug interaction susceptibility. These risks can be effectively assessed and/or mitigated if human metabolic profile of the drug candidate could reliably be determined in early development. However, currently available in vitro human models (e.g., liver microsomes, hepatocytes) are often inadequate in this regard. Furthermore, the conduct of definitive radiolabeled human ADME studies is an expensive and time-consuming endeavor that is more suited for later in development when the risk of failure has been reduced. We evaluated a recently developed chimeric mouse model with humanized liver on uPA/SCID background for its ability to predict human disposition of four model drugs (lamotrigine, diclofenac, MRK-A, and propafenone) that are known to exhibit human-specific metabolism. The results from these studies demonstrate that chimeric mice were able to reproduce the human-specific metabolite profile for lamotrigine, diclofenac, and MRK-A. In the case of propafenone, however, the human-specific metabolism was not detected as a predominant pathway, and the metabolite profiles in native and humanized mice were similar; this was attributed to the presence of residual highly active propafenone-metabolizing mouse enzymes in chimeric mice. Overall, the data indicate that the chimeric mice with humanized liver have the potential to be a useful tool for the prediction of human-specific metabolism of xenobiotics and warrant further investigation.

  20. Guidelines for the Use of Antiretroviral Agents in Pediatric HIV Infection. Vol. 47/No. RR-4.

    DTIC Science & Technology

    1998-04-17

    antihista- mines (e.g., astemizole or terfenadine); sedative-hypnotics (e.g., alprazolam , midazolam, or triazolam); calcium channel blockers (e.g...acetate, propafenone, or quinidine); ergot alkaloid derivatives; cisapride; sedative-hypnotics (e.g., alprazolam , clorazepate, diazepam, estazo- lam

  1. Pharmacologic conversion of atrial fibrillation: a systematic review of available evidence.

    PubMed

    Slavik, R S; Tisdale, J E; Borzak, S

    2001-01-01

    This report reviews the efficacy of currently available antiarrhythmic agents for conversion of atrial fibrilation (AF) to normal sinus rhythm (NSR). A systematic search of literature in the English language was done on computerized databases, such as MEDLINE, EMBASE, and Current Contents, in reference lists, by manual searching, and in contact with expert informants. Published studies involving humans that described the use of antiarrhythmic therapy for conversion of AF to NSR were considered and only studies that examined the use of agents currently available in the United States were included. Studies exclusively describing antiarrhythmic therapy for conversion of postsurgical AF were excluded. The methodology and results of each trial were assessed and attempts were made to acquire additional information from investigators when needed. Assessment of methodological quality was incorporated into a levels-of-evidence scheme. Eighty-eight trials were included, of which 34 (39%) included a placebo group (level I data). We found in recent-onset AF of less than 7 days, intravenous (i.v.) procainamide, high-dose i.v. or high-dose combination i.v. and oral amiodarone, oral quinidine, oral flecainide, oral propafenone, and high-dose oral amiodarone are more effective than placebo for converting AF to NSR. In recent-onset AF of less than 90 days, i.v. ibutilide is more effective than placebo and i.v. procainamide. In chronic AF, oral dofetilide converts AF to NSR within 72 hours, and oral propafenone and amiodarone are effective after 30 days of therapy. We conclude than for conversion of recent-onset AF of less than 7 days, procainamide may be considered a preferred i.v. agent and propafenone a preferred oral agent. For conversion of recent-onset AF of longer duration (less than 90 days), i.v. ibutilide may be considered a preferred agent. For patients with chronic AF and left ventricular dysfunction, direct current cardioversion is the preferred conversion method. Larger, well-designed randomized controlled trials with clinically important endpoints in specific populations of AF patients are needed. Copyright 2001 by W.B. Saunders Company

  2. Coexistence of Wolff-Parkinson-white and Brugada syndrome: mere curiosity?

    PubMed

    Kaiser, Elisabeth; Sacilotto, Luciana; Darrieux, Francisco; Sosa, Eduardo

    2014-09-01

    The association between Brugada syndrome (BS) and ventricular preexcitation is a rare condition, with sporadic cases already reported. We report the case of a 29-year-old man, with palpitation unrelated to physical or emotional stress. The electrocardiogram of the first visit revealed a ventricular preexcitation pattern and an end-conduction delay, with negative T wave in V1 and intraventricular conduction disturbance in V2 (atypical for BS). The typical aspect of BS occurred after introduction of propafenone for the prevention of atrioventricular tachycardia. We discuss the recognition of this rare association, the proarrhythmic effects of some drugs, treatment options, and prognosis. © 2014 Wiley Periodicals, Inc.

  3. [Atrial fibrillation].

    PubMed

    Spinar, J; Vítovec, J

    2003-09-01

    Atrial fibrilation is the most frequent arrhythmia, the occurrence increasing with age and associated diseases. The incidence at the age below 60 years is markedly lower than one per cent, whereas in persons above 80 years of age it exceeds six per cent. The occurrence in patients with heart failure is from 10% (NYHA II) up to 50% (NYHA IV). Atrial fibrillation is classified into that observed for the first time and permanent, respectively, while transient forms include paroxyzmal and persistent atrial fibrillation. The diagnosis is based on ECG recording, while echocardiography is most significant. The therapy includes two basic questions--anticoagulant or anti-aggregation treatment and the control of rhythm or frequency. The anticoagulant therapy should be introduced in all patients, where contraindications are not present, being necessary before every cardioversion, provided atrial fibrillation lasts more than two days. In patients without any heart disease and with a physiological echocardiogram it is possible to administer only anti-aggregation treatment. Cardioversion (the control of rhythm) is recommended to all symptomatic patients, in other cases and especially in older persons the control of frequency is safer and of more advantage. Electrical cardioversion is more effective that a pharmacological treatment, the sinus rhythm is preferably controlled by dofetilid, ibutilid, propafenon and amiodaron. For the control of heart rate beta-blockers, diltiazem, verapamil and digitalis are recommended.

  4. Electrophysiological mapping and histological examinations of the swine atrium with sustained (> or =24 h) atrial fibrillation: a suitable animal model for studying human atrial fibrillation.

    PubMed

    Lin, Jiunn-Lee; Lai, Ling-Ping; Lin, Chih-Shen; Du, Chao-Cheng; Wu, Tsu-Juey; Chen, Shih-Ping; Lee, Wen-Chuan; Yang, Ping-Cheng; Tseng, Yung-Zu; Lien, Wen-Pin; Huang, Shoei K Stephen

    2003-01-01

    Interventional elimination of chronic persistent atrial fibrillation (AFib) remains difficult. An animal model mimicking the clinical situation is important. Twenty-five adult pigs were implanted with a high-speed atrial pacemaker. After continuous pacing at 600 bpm for 6 weeks, 20 (91%) of the 22 survivals developed sustained AFib lasting for at least 24 h. Epicardial dense mapping revealed multiple coexisting reentrant wavelets in the left and the right atrium (LA and RA, respectively; 10.6 +/- 2.9 vs. 7.6 +/- 2.4 wavelets/cm(2)/s; p < 0.002). The mean local A-A intervals were 87.2 +/- 14.6 ms in the LA and 103.3 +/- 19.0 ms in the RA (p < 0.0002). Acute termination of sustained AFib was successful in 3 of the 5 pigs by propafenone, but in none of the 6 by dl-sotalol. Epicardial cryothermal ablation failed to terminate any AFib by compartmentalization of the RA free wall alone (4 pigs) or together with the LA appendage (4 pigs). Electron microscopic examination demonstrated diffuse perinuclear myolysis, myofibrillar fragmentation and mitochondrial crystal disruption in the atrium. Pacing-induced sustained AFib (> or =24 h) in adult pigs is a feasible and efficient animal model with electrophysiological and histological characteristics closely similar to those seen in humans. Copyright 2003 S. Karger AG, Basel

  5. Antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation.

    PubMed

    Lafuente-Lafuente, Carmelo; Valembois, Lucie; Bergmann, Jean-François; Belmin, Joël

    2015-03-28

    Atrial fibrillation is the most frequent sustained arrhythmia. Atrial fibrillation frequently recurs after restoration of normal sinus rhythm. Antiarrhythmic drugs have been widely used to prevent recurrence, but the effect of these drugs on mortality and other clinical outcomes is unclear. This is an update of a review previously published in 2008 and 2012. To determine in patients who have recovered sinus rhythm after having atrial fibrillation, the effects of long-term treatment with antiarrhythmic drugs on death, stroke, embolism, drug adverse effects and recurrence of atrial fibrillation. We updated the searches of CENTRAL in The Cochrane Library (2013, Issue 12 of 12), MEDLINE (to January 2014) and EMBASE (to January 2014). The reference lists of retrieved articles, recent reviews and meta-analyses were checked. Two independent authors selected randomised controlled trials comparing any antiarrhythmic drug with a control (no treatment, placebo, drugs for rate control) or with another antiarrhythmic drug in adults who had atrial fibrillation and in whom sinus rhythm was restored. Post-operative atrial fibrillation was excluded. Two authors independently assessed quality and extracted data. Studies were pooled, if appropriate, using Peto odds ratio (OR). All results were calculated at one year of follow-up. In this update three new studies, with 534 patients, were included making a total of 59 included studies comprising 21,305 patients. All included studies were randomised controlled trials. Allocation concealment was adequate in 17 trials, it was unclear in the remaining 42 trials. Risk of bias was assessed in all domains only in the trials included in this update.Compared with controls, class IA drugs quinidine and disopyramide (OR 2.39, 95% confidence interval (95% CI) 1.03 to 5.59, number needed to treat to harm (NNTH) 109, 95% CI 34 to 4985) and sotalol (OR 2.23, 95% CI 1.1 to 4.50, NNTH 169, 95% CI 60 to 2068) were associated with increased all-cause mortality. Other antiarrhythmics did not seem to modify mortality, but our data could be underpowered to detect mild increases in mortality for several of the drugs studied.Several class IA (disopyramide, quinidine), IC (flecainide, propafenone) and III (amiodarone, dofetilide, dronedarone, sotalol) drugs significantly reduced recurrence of atrial fibrillation (OR 0.19 to 0.70, number needed to treat to beneft (NNTB) 3 to 16). Beta-blockers (metoprolol) also significantly reduced atrial fibrillation recurrences (OR 0.62, 95% CI 0.44 to 0.88, NNTB 9).All analysed drugs increased withdrawals due to adverse affects and all but amiodarone, dronedarone and propafenone increased pro-arrhythmia. Only 11 trials reported data on stroke. None of them found any significant difference with the exception of a single trial than found less strokes in the group treated with dronedarone compared to placebo. This finding was not confirmed in others studies on dronedarone.We could not analyse heart failure and use of anticoagulation because few original studies reported on these measures. Several class IA, IC and III drugs, as well as class II drugs (beta-blockers), are moderately effective in maintaining sinus rhythm after conversion of atrial fibrillation. However, they increase adverse events, including pro-arrhythmia, and some of them (disopyramide, quinidine and sotalol) may increase mortality. Possible benefits on clinically relevant outcomes (stroke, embolism, heart failure) remain to be established.

  6. Contemporary clinical trials in ventricular tachycardia and fibrillation: implications of ESVEM, CASCADE, and CASH for clinical management.

    PubMed

    Anderson, J L

    1995-10-01

    Recent clinical trials in patients with ventricular tachycardia (VT) or fibrillation (VF) have occurred in the setting of the disappointing results of postinfarction secondary prevention studies using Class I antiarrhythmics (e.g., CAST). ESVEM addressed in a randomized trial whether electrophysiologic study (EPS) or Holter monitoring (HM) is a more accurate predictor of long-term antiarrhythmic drug efficacy in VT/VF patients (N=486) and what the relative efficacy of various antiarrhythmic agents is for VT/VF. Surprisingly, arrhythmia recurrence rates were not significantly different by the method of determining an efficacy prediction. However, arrhythmia recurrence and mortality were lower (by about 50% at 1 year) in patients treated with sotalol (a mixed Class II/III agent) than with other drugs (Class I). CASCADE evaluated empiric amiodarone versus guided (EPS or HM) standard (Class I) therapy in survivors of out-of-hospital cardiac arrest due to VF. The primary endpoint of cardiac death, resuscitated VF, or syncopal shock (in ICD patients) was reduced by amiodarone compared with conventional therapy (9% vs 23% at 1 year). An interim report of the ongoing CASH study suggested in 230 survivors of cardiac arrest that propafenone (Class IC) provided less effective prophylaxis (approximately 20% 1-year mortality) compared with randomly assigned therapies with amiodarone, metoprolol, or an ICD (approximately 14% mortality rates) and was excluded from further study. These studies have led to a paradigm shift in the approach to antiarrhythmic therapy of VT/VF: drugs with antisympathetic plus Class III (refractoriness prolonging) action (i.e., sotalol, amiodarone) are superior to traditional drugs with Class I( conduction slowing) effects, even when guided by EPS or HM.

  7. Paroxysmal atrial fibrillation: dynamics of the main antioxidant enzymes--superoxide dismutase and catalase.

    PubMed

    Negreva, Mariya N; Penev, Atanas P; Georgiev, Svetoslav Zh; Aleksandrova, Albena A

    2014-01-01

    Researchers have a particularly strong interest in the mechanisms implicated in the clinical manifestation of atrial fibrillation. To examine dynamically the activity of the antioxidant enzymes, superoxide dismutase and catalase in patients with paroxysmal atrial fibrillation (duration < 48 hours). The studied parameters were examined in the erythrocytes of 51 patients (59.84 +/- 1.60, 26 men) immediately after their hospitalization, at 24 hours and 28 days after restoration of sinus rhythm. 52 controls (59.50 +/- 1.46, 26 men) were also included, none of which had a history of arrhythmia. Propafenone was used to manage the rhythm abnormality. The enzyme activity was determined by a spectrophotometric method. The average duration of atrial fibrillation episodes until the time of hospitalization was 8.14 hours (from 2 to 24 hours). During patient hospitalization the activity of superoxide dismutase and catalase was considerably higher compared to that of the controls (8.46 +/- 0.26 vs 5.81 +/- 0.14 U/mg Hb; 7.36 +/- 0.25 vs 4.76 +/- 0.12 E240/min/mg Hb; P < 0.001). This difference was maintained 24 hours after the rhythm regularization (7.19 +/- 0.25 vs 5.81 +/- 0.14 U/mg Hb, p < 0.001; 5.30 +/- 0.21 vs 4.76 +/- 0.12 E240/min/mg Hb, p < 0.05). Twenty-eight days after the restoration of sinus rhythm, the activity of catalase remained increased (5.11 +/- 0.08 vs 4.76 +/- 0.12 E240/min/mg Hb, p < 0.05). The paroxysmal atrial fibrillation in our study was characterized with significantly increased activity of superoxide dismutase and catalase even in the early hours of clinical manifestation of the disorder, which then slowly decreased with the restoration of sinus rhythm. Therefore, we can conclude that changes in oxidative status are closely related to the disease and are probably a part of the intimate mechanisms related to its initiation and clinical course.

  8. Management of atrial fibrillation in seven European countries after the publication of the 2010 ESC Guidelines on atrial fibrillation: primary results of the PREvention oF thromboemolic events--European Registry in Atrial Fibrillation (PREFER in AF).

    PubMed

    Kirchhof, Paulus; Ammentorp, Bettina; Darius, Harald; De Caterina, Raffaele; Le Heuzey, Jean-Yves; Schilling, Richard John; Schmitt, Josef; Zamorano, Jose Luis

    2014-01-01

    We sought to describe the management of patients with atrial fibrillation (AF) in Europe after the release of the 2010 AF Guidelines of the European Society of Cardiology. The PREFER in AF registry enrolled consecutive patients with AF from January 2012 to January 2013 in 461 centres in seven European countries. Seven thousand two hundred and forty-three evaluable patients were enrolled, aged 71.5 ± 11 years, 60.1% male, CHA2DS2VASc score 3.4 ± 1.8 (mean ± standard deviation). Thirty per cent patients had paroxysmal, 24.0% had persistent, 7.2% had long-standing persistent, and 38.8% had permanent AF. Oral anticoagulation was used in the majority of patients: 4799 patients (66.3%) received a vitamin K antagonist (VKA) as mono-therapy, 720 patients a combination of VKA and antiplatelet agents (9.9%), 442 patients (6.1%) a new oral anticoagulant drugs (NOAC). Antiplatelet agents alone were given to 808 patients (11.2%), no antithrombotic therapy to 474 patients (6.5%). Of 7034 evaluable patients, 5530 (78.6%) patients were adequately rate controlled (mean heart rate 60-100 bpm). Half of the patients (50.7%) received rhythm control therapy by electrical cardioversion (18.1%), pharmacological cardioversion (19.5%), antiarrhythmic drugs (amiodarone 24.1%, flecainide or propafenone 13.5%, sotalol 5.5%, dronedarone 4.0%), and catheter ablation (5.0%). The management of AF patients in 2012 has adapted to recent evidence and guideline recommendations. Oral anticoagulant therapy with VKA (majority) or NOACs is given to over 80% of eligible patients, including those at risk for bleeding. Rate is often adequately controlled, and rhythm control therapy is widely used.

  9. Pharmacological and electrophysiological characterization of nine, single nucleotide polymorphisms of the hERG-encoded potassium channel

    PubMed Central

    Männikkö, R; Overend, G; Perrey, C; Gavaghan, CL; Valentin, J-P; Morten, J; Armstrong, M; Pollard, CE

    2010-01-01

    Background and purpose: Potencies of compounds blocking KV11.1 [human ether-ago-go-related gene (hERG)] are commonly assessed using cell lines expressing the Caucasian wild-type (WT) variant. Here we tested whether such potencies would be different for hERG single nucleotide polymorphisms (SNPs). Experimental approach: SNPs (R176W, R181Q, Del187-189, P347S, K897T, A915V, P917L, R1047L, A1116V) and a binding-site mutant (Y652A) were expressed in Tet-On CHO-K1 cells. Potencies [mean IC50; lower/upper 95% confidence limit (CL)] of 48 hERG blockers was estimated by automated electrophysiology [IonWorks™ HT (IW)]. In phase one, rapid potency comparison of each WT-SNP combination was made for each compound. In phase two, any compound-SNP combinations from phase one where the WT upper/lower CL did not overlap with those of the SNPs were re-examined. Electrophysiological WT and SNP parameters were determined using conventional electrophysiology. Key results: IW detected the expected sixfold potency decrease for propafenone in Y652A. In phase one, the WT lower/upper CL did not overlap with those of the SNPs for 77 compound-SNP combinations. In phase two, 62/77 cases no longer yielded IC50 values with non-overlapping CLs. For seven of the remaining 15 cases, there were non-overlapping CLs but in the opposite direction. For the eight compound-SNP combinations with non-overlapping CLs in the same direction as for phase 1, potencies were never more than twofold apart. The only statistically significant electrophysiological difference was the voltage dependence of activation of R1047L. Conclusion and implications: Potencies of hERG channel blockers defined using the Caucasian WT sequence, in this in vitro assay, were representative of potencies for common SNPs. This article is part of a themed section on QT safety. To view this issue visit http://www3.interscience.wiley.com/journal/121548564/issueyear?year=2010 PMID:19673885

  10. Sotalol: An important new antiarrhythmic.

    PubMed

    Anderson, J L; Prystowsky, E N

    1999-03-01

    Sotalol, the most recently approved oral antiarrhythmic drug, has a unique pharmacologic profile. Its electrophysiology is explained by nonselective beta-blocking action as well as class III antiarrhythmic activity (including fast-activating cardiac membrane-delayed rectifier current blockade), which leads to increases in action potential duration and refractory period throughout the heart and in QT interval on the surface electrocardiogram. Its better hemodynamic tolerance than other beta-blockers may be a result of enhanced inotropy associated with class III activity. Sotalol's ability to suppress ventricular ectopy is similar to that of class I agents and better than that of standard beta-blockers. Unlike class I agents, its use in a postinfarction trial was not associated with increased mortality rate. Therapeutically, it has shown superior efficacy for prevention of recurrent ventricular tachycardia and ventricular fibrillation, which was the basis for its approval. In a randomized study, the Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) trial, sotalol was associated with an increased in-hospital efficacy prediction rate (by Holter monitor or electrophysiologic study), reduced long-term arrhythmic recurrence rate with superior tolerance, and lower mortality rate than class I ("standard") antiarrhythmic drugs. Sotalol was 1 of 2 drugs selected for comparison with implantable defibrillators in the recent National Institutes of Health Antiarrhythmics versus Implantable Defibrillator (AVID) study. Sotalol appears to be a preferred drug for use with implantable defibrillators; unlike some other agents (eg, amiodarone) it does not elevate and, indeed, may lower defibrillation threshold. Although unapproved for this use, sotalol is active against atrial arrhythmias. It has shown efficacy equivalent to propafenone and quinidine in preventing atrial fibrillation recurrence, but it is better tolerated than quinidine and provides excellent rate control during recurrence. Sotalol's major side effects are related to beta-blockade and the risk of torsades de pointes (acceptably small if appropriate precautions are taken). Unlike several other antiarrhythmics (eg, amiodarone), it has no pharmacokinetic drug-drug interactions, is not metabolized, and is entirely renally excreted. Initial dose is 80 mg twice daily, with gradual titration to 240 to 360 mg/day as needed. The daily dose must be reduced in renal failure. On the basis of favorable clinical trials and practice experience, sotalol has shown a steadily growing impact on the treatment of arrhythmias during its 5 years of market availability, a trend that is likely to continue.

  11. Dronedarone: a promising alternative for the management of atrial fibrillation.

    PubMed

    Yalta, Kenan; Turgut, Okan Onur; Yilmaz, Mehmet Birhan; Yilmaz, Ahmet; Tandogan, Izzet

    2009-10-01

    Atrial fibrillation (AF) is the most frequently encountered chronic arrhythmia associated with significant morbidity. It is generally encountered in the elderly, and will presumably become more prevalent in the future due to the increasing proportion of the elderly in the population. Major studies on AF have demonstrated no significant difference between rhythm and rate control in terms of mortality. However, young population with new-onset or lone AF, or patients in whom the maintenance of sinus rhythm is a must (due to recurrent thromboembolic events etc.) still gives rise to significant concerns related to the obligatory long-term prophylaxis. The long-term administration of the currently available conventional agents (amiodarone, dofetilide, sotalol, propafenone,flecainide etc.) is considered as a 'double edged sword' due to the presence of life-threatening adverse effects including pro-arrhythmia and organ toxicity associated with these agents. Several molecules are being developed for the management of AF. However, only a few novel agents confer promising results with respect to safety and efficacy issues in the major studies. Dronedarone is an amiodarone analogue without iodine moiety in its structure, and is similar to amiodarone with regard to its structural and electrophysiological properties. Dronedarone is largely denuded of the potentially life-threatening adverse effects of anti-arrhythmics. Major clinical studies have demonstrated both rhythm and rate-controlling efficacy of dronedarone compared to placebo without any serious adverse effects in patients with AF. However, the ANDROMEDA trial, a large scale study including patients hospitalized for symptomatic congestive heart failure (with severely depressed left ventricular systolic functions) was prematurely terminated due to the increased mortality in the dronedarone arm compared to placebo indicating a lack of safety in this group of patients. Conversely, the recently published ATHENA study (including more than 4,600 high risk patients, but excluding those with severe heart failure) demonstrated a significant reduction in cardiovascular hospitalizations and cardiovascular mortality with dronedarone compared to placebo. In contrast, the DIONYSOS study, comparing dronedarone with amiodarone, demonstrated better safety, but lower efficacy of dronedarone for the maintenance of sinus rhythm in patients with AF. Further clinical trials (including head to head comparison with other conventional anti-arrhythmics) are still required to determine the place of dronedarone in the management of AF. The present review focuses on basic and clinical aspects of dronedarone, a novel agent for the management of AF.

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