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Nigam A, Talajic M, Roy D, Nattel S, Lambert J, Nozza A, Jones P, O'Hara G, Kopecky S, Brophy J, Tardif J. Multicentre Trial of Fish Oil for the Reduction of Atrial Fibrillation Recurrence, Inflammation and Oxidative Stress: the Atrial Fibrillation Fish Oil Research Study. Can J Cardiol 2013. [DOI: 10.1016/j.cjca.2013.07.658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Roy K, Champagne J, Sarrazin J, Nault I, O'Hara G, Blier L, Molin F, Philippon F. ICD Generator Change With a Functional Sprint Fidelis Lead: Reuse It or Not? Can J Cardiol 2013. [DOI: 10.1016/j.cjca.2013.07.309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Steinberg C, Sarrazin J, Champagne J, Philippon F, Nault I, Molin F, Blier L, O'Hara G. High Annual Incidence of New Riata Insulation Defects in a Prospective Cohort. Can J Cardiol 2013. [DOI: 10.1016/j.cjca.2013.07.311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Steinberg C, Sarrazin J, Champagne J, Philippon F, Molin F, Nault I, Blier L, O'Hara G. High Voltage Testing of Riata Defibrillation Leads With Insulation Defects - a Single Center Experience. Can J Cardiol 2013. [DOI: 10.1016/j.cjca.2013.07.615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Steinberg C, Sarrazin J, Champagne J, Philippon F, Molin F, Nault I, Blier L, O'Hara G. Pa/Lateral Chest X-Ray Is Non-Inferior to Fluoroscopy for the Detection of Insulation Defects in Riata Defibrillation Leads. Can J Cardiol 2013. [DOI: 10.1016/j.cjca.2013.07.616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Steinberg C, Sarrazin J, Bouchard M, Philippon F, O'Hara G, Molin F, Nault I, Blier L, Champagne J. 765 High Prevalence of Riata Insulation Defects Detected by Systematic PA/Lateral Chest-X Ray - A Single Center Experience. Can J Cardiol 2012. [DOI: 10.1016/j.cjca.2012.07.690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Barnes E, Folgori A, Capone S, Swadling L, Aston S, Kurioka A, Meyer J, Huddart R, Smith K, Townsend R, Brown A, Antrobus R, Ammendola V, Naddeo M, O'Hara G, Willberg C, Harrison A, Grazioli F, Esposito ML, Siani L, Traboni C, Oo Y, Adams D, Hill A, Colloca S, Nicosia A, Cortese R, Klenerman P. Novel adenovirus-based vaccines induce broad and sustained T cell responses to HCV in man. Sci Transl Med 2012. [PMID: 22218690 DOI: 10.1126/scitranslmed.300315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Currently, no vaccine exists for hepatitis C virus (HCV), a major pathogen thought to infect 170 million people globally. Many studies suggest that host T cell responses are critical for spontaneous resolution of disease, and preclinical studies have indicated a requirement for T cells in protection against challenge. We aimed to elicit HCV-specific T cells with the potential for protection using a recombinant adenoviral vector strategy in a phase 1 study of healthy human volunteers. Two adenoviral vectors expressing NS proteins from HCV genotype 1B were constructed based on rare serotypes [human adenovirus 6 (Ad6) and chimpanzee adenovirus 3 (ChAd3)]. Both vectors primed T cell responses against HCV proteins; these T cell responses targeted multiple proteins and were capable of recognizing heterologous strains (genotypes 1A and 3A). HCV-specific T cells consisted of both CD4+ and CD8+ T cell subsets; secreted interleukin-2, interferon-γ, and tumor necrosis factor-α; and could be sustained for at least a year after boosting with the heterologous adenoviral vector. Studies using major histocompatibility complex peptide tetramers revealed long-lived central and effector memory pools that retained polyfunctionality and proliferative capacity. These data indicate that an adenoviral vector strategy can induce sustained T cell responses of a magnitude and quality associated with protective immunity and open the way for studies of prophylactic and therapeutic vaccines for HCV.
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Mokrani B, Champagne J, Philippon F, O'Hara G, Naults I, Zannad N, Molin F, Blier L, Sarrazin J. 344 Pulmonary vein isolation for paroxysmal atrial fibrillation using cryoballoon: The initial canadian experience. Can J Cardiol 2011. [DOI: 10.1016/j.cjca.2011.07.294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
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Mokrani B, Champagne J, Sarrazin J, Philippon F, O'Hara G, Gingras M, Zannad N, Blier L, Molin F, Naults I. 584 Silent cerebral thromboembolic lesions on MRI following atrial fibrillation ablation with different technologies. Can J Cardiol 2011. [DOI: 10.1016/j.cjca.2011.07.484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
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Mokrani B, Molin F, O'Hara G, Blier L, Champagne J, Sarrazin J, Naults I, Zannad N, Philippon F. 561 Percutaneous lead extraction using the evolution™ system: A single centre experience. Can J Cardiol 2011. [DOI: 10.1016/j.cjca.2011.07.465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Mokrani B, Sarrazin J, Naults I, O'Hara G, Zannad N, Blier L, Philippon F, Molin F, Champagne J. 270 Short-term results of pulmonary vein isolation for paroxysmal atrial fibrillation using duty-cycled bipolar and unipolar radiofrequency energy: The initial Québec experience. Can J Cardiol 2011. [DOI: 10.1016/j.cjca.2011.07.202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
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Mokrani B, Sarrazin J, Champagne J, Naults I, Zannad N, Blier L, Philippon F, Molin F, O'Hara G. 345 Prospective study comparing duty-cycled bipolar and unipolar radiofrequency to pulmonary vein isolation by point-by-point ablation and cryoballoon ablation. Can J Cardiol 2011. [DOI: 10.1016/j.cjca.2011.07.295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
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Sarrazin J, Philippon F, Tessier M, Guimond J, Nadeau M, Molin F, Champagne J, Trottier M, Nault I, Blier L, O'Hara G. 555 18F-FDG PET/CT as a new imaging modality for diagnosis of cardiac device infections (PET-ID). Can J Cardiol 2011. [DOI: 10.1016/j.cjca.2011.07.459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Hutchinson S, Sims S, O'Hara G, Silk J, Gileadi U, Cerundolo V, Klenerman P. A dominant role for the immunoproteasome in CD8+ T cell responses to murine cytomegalovirus. PLoS One 2011; 6:e14646. [PMID: 21304910 PMCID: PMC3033404 DOI: 10.1371/journal.pone.0014646] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 01/06/2011] [Indexed: 01/08/2023] Open
Abstract
Murine cytomegalovirus (MCMV) is an important animal model of human cytomegalovirus (HCMV), a β-Herpesvirus that infects the majority of the world's population and causes disease in neonates and immunocompromised adults. CD8+ T cells are a major part of the immune response to MCMV and HCMV. Processing of peptides for presentation to CD8+ T cells may be critically dependent on the immunoproteasome, expression of which is affected by MCMV. However, the overall importance of the immunoproteasome in the generation of immunodominant peptides from MCMV is not known. We therefore examined the role of the immunoproteasome in stimulation of CD8+ T cell responses to MCMV – both conventional memory responses and those undergoing long-term expansion or “inflation”. We infected LMP7−/− and C57BL/6 mice with MCMV or with newly-generated recombinant vaccinia viruses (rVVs) encoding the immunodominant MCMV protein M45 in either full-length or epitope-only minigene form. We analysed CD8+ T cell responses using intracellular cytokine stain (ICS) and MHC Class I tetramer staining for a panel of MCMV-derived epitopes. We showed a critical role for immunoproteasome in MCMV affecting all epitopes studied. Interestingly we found that memory “inflating” epitopes demonstrate reduced immunoproteasome dependence compared to non-inflating epitopes. M45-specific responses induced by rVVs remain immunoproteasome-dependent. These results help to define a critical restriction point for CD8+ T cell epitopes in natural cytomegalovirus (CMV) infection and potentially in vaccine strategies against this and other viruses.
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O'Hara G. On the front line: The Somalia diary. Assoc Med J 2007. [DOI: 10.1136/sbmj.070132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Champagne J, Cantin B, Philippon E, Gilbert M, O'Hara G, Molin F, Robitaille M, Dagenais G. 11.3 Prevalence, prognostic and electrocardiographic patterns of the brugada syndrome in the quebec cardiovascular study. Europace 2003. [DOI: 10.1016/eupace/4.supplement_1.a18-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Champagne J, Boucher G, O'Hara G, Philippon F, Molin F, Blier L, Gilbert M. 9.7 Outcome of patients with hemodynamically stable ventricular tachycardia. Europace 2003. [DOI: 10.1016/eupace/4.supplement_1.a16-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Champagne J, Molin E, O'Hara G, Philippon F, Gilbert M, Charbonneau L, Chahine M. 11.2 Utility and role of a teaching program for physicians to identify brugada syndrome: experience of the quebec heart institute with a French canadian population. Europace 2003. [DOI: 10.1016/eupace/4.supplement_1.a18-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Champagne J, O'Hara G, Molin F, Philippon F, Chahine M, Poirier P, Charbonneau L, Gilbert M. 11.8 Utility of the I.V. procainamide test to unmask a concealed form of Brugada syndrome. Europace 2003. [DOI: 10.1016/eupace/4.supplement_1.a19-d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Lamarche J, O'Hara G, Philippon F, Gilbert M, Daleau P. Molecular analysis of connexin 40 in the familial form of atrial fibrillation. Eur Heart J 2001; 22:1511-2. [PMID: 11482925 DOI: 10.1053/euhj.2001.2668] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Langdeau JB, Blier L, Turcotte H, O'Hara G, Boulet LP. Electrocardiographic findings in athletes: the prevalence of left ventricular hypertrophy and conduction defects. Can J Cardiol 2001; 17:655-9. [PMID: 11420576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
OBJECTIVES To determine whether there are electrocardiographic differences or distinctive abnormalities between athletes and sedentary subjects, and to verify the relationship between vagal activity measured by heart rate variability (SD of all normal-to-normal intervals [SDNN]) and possible electrocardiographic abnormalities. SUBJECTS AND METHODS Resting electrocardiograms and heart rate variability measurements were performed separately during a single visit on 100 athletes and 50 nonathlete control subjects aged 18 to 55 years. The athletes were from the following various sports disciplines: long-distance running, mountain biking, cross-country skiing, biathlon, speed skating, swimming and triathlon. RESULTS AND CONCLUSIONS There were significantly longer RR intervals, PR intervals and QT intervals in athletes than in control subjects (all P<0.05). The QRS complex and QTc did not show significant differences (both P>0.05). The prevalence of left ventricular hypertrophy (LVH) and incomplete right bundle branch block (IRBBB) was 10% and 7%, respectively, in athletes, but these conditions were absent in control subjects; among athletes, 2% presented with both conditions. LVH and IRBBB were more common among long-distance runners (six of 14 and four of 14, respectively) and could be attributed to normal, long term adaptation to intense, repeated exercise. LVH was related to age (P=0.04), whereas IRBBB was influenced by the number of years of training in the respective sports discipline (P=0.03). The mean SDNN value was significantly more elevated in athletes (P=0.0001), reflecting a higher parasympathetic tone than in sedentary control subjects. However, there was no relationship between vagal activity and LVH or IRBBB (both P>0.05).
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Lessard E, Yessine MA, Hamelin BA, Gauvin C, Labbé L, O'Hara G, LeBlanc J, Turgeon J. Diphenhydramine alters the disposition of venlafaxine through inhibition of CYP2D6 activity in humans. J Clin Psychopharmacol 2001; 21:175-84. [PMID: 11270914 DOI: 10.1097/00004714-200104000-00009] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
CYP2D6 is the major enzyme involved in the metabolism of venlafaxine. Subjects with a low CYP2D6 activity have increased plasma concentrations of venlafaxine that may predispose them to cardiovascular side effects. In vitro and in vivo studies showed that diphenhydramine, a nonprescription antihistamine, can inhibit CYP2D6 activity. Therefore, the authors investigated in this study a potential drug interaction between diphenhydramine and venlafaxine. Fifteen male volunteers, nine with the extensive metabolizer (EM) and six with the poor metabolizer (PM) phenotype of CYP2D6, received venlafaxine hydrochloride 18.75 mg orally every 12 hours for 48 hours on two occasions (1 week apart): once alone and once during the concomitant administration of diphenhydramine hydrochloride (50 mg every 12 hours). Blood and urine samples were collected for 12 hours under steady-state conditions. In EMs, diphenhydramine decreased venlafaxine oral clearance from 104+/-60 L/hr to 43+/-23 L/hr (mean +/- SD; p < 0.05) without any effect on renal clearance (4+/-1 L/hr during venlafaxine alone and 4+/-2 L/hr during venlafaxine plus diphenhydramine). In PMs, coadministration of diphenhydramine did not cause significant changes in oral clearance and partial metabolic clearances of venlafaxine to its various metabolites. Diphenhydramine disposition was only slightly affected by genetically determined low CYP2D6 activity or concomitant administration of venlafaxine. In conclusion, diphenhydramine, at therapeutic doses, inhibits CYP2D6-mediated metabolism of venlafaxine in humans. Clinically significant interactions could be encountered during the concomitant administration of diphenhydramine and other antidepressant or antipsychotic drugs that are substrates of CYP2D6.
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Labbé L, O'Hara G, Lefebvre M, Lessard E, Gilbert M, Adedoyin A, Champagne J, Hamelin B, Turgeon J. Pharmacokinetic and pharmacodynamic interaction between mexiletine and propafenone in human beings. Clin Pharmacol Ther 2000; 68:44-57. [PMID: 10945315 DOI: 10.1067/mcp.2000.108023] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND OBJECTIVE Mexiletine and propafenone are often used concomitantly and are metabolized by the same cytochrome P450 isozymes, namely CYP2D6, CYP1A2, and probably CYP3A4. Our objective was to study the potential pharmacokinetic and electrophysiological interactions between mexiletine and propafenone. METHODS Fifteen healthy volunteers, 8 extensive metabolizers and 7 poor metabolizers of CYP2D6, received oral doses of mexiletine 100 mg two times daily from day 1 to day 8 and oral doses of propafenone 150 mg two times daily from day 5 to day 12. Interdose studies were performed at steady-state on mexiletine alone (day 4), mexiletine plus propafenone (day 8), and propafenone alone (day 12). RESULTS In subjects in the extensive metabolizer group, coadministration of propafenone decreased oral clearances of R-(-)-mexiletine (from 41+/-11 L/h to 28+/-7 L/h) and S-(+)-mexiletine (from 43+/-15 L/h to 29+/-11 L/h) to an extent such that these values were no longer different between the extensive and the poor metabolizer groups. Propafenone coadministration also decreased partial metabolic clearances of mexiletine to hydroxymethylmexiletine, p-hydroxymexiletine, and m-hydroxymexiletine in extensive metabolizers by 71%, 67%, and 73%, respectively. In contrast, propafenone did not alter the kinetics of mexiletine enantiomers in subjects in the poor metabolizer group except for a slight decrease in the formation of hydroxymethylmexiletine. Pharmacokinetic parameters of propafenone were not changed during concomitant administration of mexiletine in subjects of either phenotype. Finally, electrocardiographic parameters (QRS duration, QTc, RR, and PR intervals) were not modified during the combined administration of the drugs. CONCLUSION Propafenone is a potent CYP2D6 inhibitor that may cause an increase in plasma concentrations of coadministered CYP2D6 substrates.
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Lessard E, Hamelin BA, Labbé L, O'Hara G, Bélanger PM, Turgeon J. Involvement of CYP2D6 activity in the N-oxidation of procainamide in man. PHARMACOGENETICS 1999; 9:683-96. [PMID: 10634131 DOI: 10.1097/01213011-199912000-00003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Occurrence of a lupus-like syndrome in a significant number of patients treated with procainamide has limited the clinical use of this antiarrhythmic drug. In-vitro studies conducted in our laboratory have demonstrated that CYP2D6 is the major cytochrome P450 isozyme involved in the formation of N-hydroxyprocainamide, a metabolite potentially involved in the drug-induced lupus erythematosus syndrome observed with procainamide. In the current study, we evaluated the role of CYP2D6 activity in the in-vivo oxidation of procainamide in man. Nineteen healthy individuals, 13 with high (extensive metabolizers) and six with low (poor metabolizers) CYP2D6 activity, received a single 500 mg oral dose of procainamide hydrochloride on two occasions, once alone (period 1) and once during the concomitant administration of the selective inhibitor quinidine (50 mg four times daily; period 2). Blood and urine samples were collected over 36 h after drug administration of procainamide and analysed for procainamide and its major metabolites (N-acetylprocainamide, desethylprocainamide, N-acetyl-desethylprocainamide, p-aminobenzoic acid and its N-acetylated derivative, and nitroprocainamide). No differences were observed in the oral and renal clearances of procainamide between extensive metabolizers and poor metabolizers during either study period. However, partial metabolic clearance of procainamide to desethylprocainamide was significantly greater in extensive metabolizers than in poor metabolizers during both periods. Most importantly, the urinary excretion of nitroprocainamide during period 1 was measurable in 7/13 extensive metabolizers but in none of the poor metabolizers. During the concomitant administration of quinidine, nitroprocainamide could not be detected in the urine of any individuals tested. Therefore, our results suggest that CYP2D6 is involved in the in-vivo aliphatic amine deethylation and N-oxidation of procainamide at its arylamine function in man. Further studies are needed to demonstrate whether a low CYP2D6 activity, either genetically determined or pharmacologically modulated, could prevent drug-induced lupus erythematosus syndrome observed during chronic therapy with procainamide.
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Lessard E, Yessine MA, Hamelin BA, O'Hara G, LeBlanc J, Turgeon J. Influence of CYP2D6 activity on the disposition and cardiovascular toxicity of the antidepressant agent venlafaxine in humans. PHARMACOGENETICS 1999; 9:435-43. [PMID: 10780263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
According to in-vitro studies with microsomes from human livers and from yeast expression systems with high CYP2D6 activity, the major oxidation pathway of venlafaxine is catalysed by CYP2D6. In this study, we investigated the role of the CYP2D6 polymorphism and the effects of low-dose quinidine, a selective inhibitor of, CYP2D6, on the disposition of venlafaxine. Fourteen healthy men, eight with the extensive metabolizer and six with the poor metabolizer phenotype were administered venlafaxine hydrochloride 18.75 mg orally every 12 h for 48 h on two occasions (1 week apart); once alone and once during the concomitant administration of quinidine sulfate 100 mg every 12 h. Blood and urine samples were collected under steady-state conditions over one dosing interval (12 h). When venlafaxine was administered alone, the oral clearance of venlafaxine was more than fourfold less in poor metabolizers compared to extensive metabolizers (P < 0.05). This was mainly due to a decreased capability of poor metabolizers to form O-desmethylated metabolites at the position 4 of the aromatic moiety. In extensive metabolizers, quinidine decreased venlafaxine oral clearance from 100 +/- 62 l/h to 17 +/- 5 l/h (mean +/- SD; P < 0.05) without any effects on renal clearance (4 +/- 1 l/h during venlafaxine alone and 4 +/- 1 l/h during venlafaxine plus quinidine). In these individuals, the sequential metabolism of venlafaxine to O-desmethylvenlafaxine and to N,O-didesmethylvenlafaxine was inhibited by quinidine coadministration so that metabolic clearances to O-desmethylated metabolites decreased from 43 +/- 32 l/h to 2 +/- 1 l/h (P < 0.05). In poor metabolizers, coadministration of quinidine did not cause significant changes in oral clearance and partial metabolic clearances of venlafaxine to its various metabolites. Decreased CYP2D6 activity could also be associated with cardiovascular toxicity as observed in four patients during treatment with the drug. Thus, genetically determined or pharmacologically altered CYP2D6 activity represents a major determinant of venlafaxine disposition in humans.
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