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Kharasch ED, Lenze EJ. Pharmacogenetic Influence on Stereoselective Steady-State Disposition of Bupropion. Drug Metab Dispos 2024; 52:455-466. [PMID: 38467432 PMCID: PMC11023817 DOI: 10.1124/dmd.124.001697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/02/2024] [Accepted: 03/07/2024] [Indexed: 03/13/2024] Open
Abstract
Bupropion is used for treating depression, obesity, and seasonal affective disorder, and for smoking cessation. Bupropion is commonly prescribed, but has complex pharmacokinetics and interindividual variability in metabolism and bioactivation may influence therapeutic response, tolerability, and safety. Bupropion is extensively and stereoselectively metabolized, the metabolites are pharmacologically active, and allelic variation in cytochrome P450 (CYP) 2B6 affects clinical hydroxylation of single-dose bupropion. Genetic effects on stereoselective disposition of steady-state bupropion are not known. In this preplanned secondary analysis of a prospective, randomized, double-blinded, crossover study which compared brand and generic bupropion XL 300 mg drug products, we measured steady-state enantiomeric plasma and urine parent bupropion and primary and secondary metabolite concentrations. This investigation evaluated the influence of genetic polymorphisms in CYP2B6, CYP2C19, and P450 oxidoreductase on the disposition of Valeant Pharmaceuticals Wellbutrin brand bupropion in 67 participants with major depressive disorder. We found that hydroxylation of both bupropion enantiomers was lower in carriers of the CYP2B6*6 allele and in carriers of the CYP2B6 516G>T variant, with correspondingly greater bupropion and lesser hydroxybupropion plasma concentrations. Hydroxylation was 25-50% lower in CYP2B6*6 carriers and one-third to one-half less in 516T carriers. Hydroxylation of the bupropion enantiomers was comparably affected by CYP2B6 variants. CYP2C19 polymorphisms did not influence bupropion plasma concentrations or hydroxybupropion formation but did influence the minor pathway of 4'-hydroxylation of bupropion and primary metabolites. P450 oxidoreductase variants did not influence bupropion disposition. Results show that CYP2B6 genetic variants affect steady-state metabolism and bioactivation of Valeant brand bupropion, which may influence therapeutic outcomes. SIGNIFICANCE STATEMENT: Bupropion, used for depression, obesity, and smoking cessation, undergoes metabolic bioactivation, with incompletely elucidated interindividual variability. We evaluated cytochrome P450 (CYP) 2B6, CYP2C19 and P450 oxidoreductase genetic variants and steady-state bupropion and metabolite enantiomers disposition. Both enantiomers hydroxylation was lower in CYP2B6*6 and CYP2B6 516G>T carriers, with greater bupropion and lesser hydroxybupropion plasma concentrations. CYP2C19 polymorphisms did not affect bupropion or hydroxybupropion but did influence minor 4'-hydroxylation of bupropion and primary metabolites. CYP2B6 variants affect steady-state bupropion bioactivation, which may influence therapeutic outcomes.
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Affiliation(s)
- Evan D Kharasch
- Department of Anesthesiology, Duke University, Durham, North Carolina (E.D.K.); Bermaride, LLC (E.D.K.); and Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri (E.J.L.)
| | - Eric J Lenze
- Department of Anesthesiology, Duke University, Durham, North Carolina (E.D.K.); Bermaride, LLC (E.D.K.); and Department of Psychiatry, Washington University in St. Louis, St. Louis, Missouri (E.J.L.)
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Zhang L, Meng X, Dong P, Qi T, Liu L, Wang B. Effects of rifampicin, CYP2B6 and ABCB1 polymorphisms on efavirenz plasma concentration in Chinese patients living with HIV and tuberculosis. Int J STD AIDS 2023; 34:37-47. [PMID: 36356965 DOI: 10.1177/09564624221134137] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Tuberculosis (TB) is the leading opportunistic infection of people living with human immunodeficiency virus (HIV; PLWH). Cytochrome P450 (CYP) 2B6 and ATP-binding cassette sub-family B member 1 (ABCB1) are involved in the metabolism and transportation of efavirenz. The study was aimed to investigate the effects of rifampicin, CYP2B6 and ABCB1 polymorphisms on efavirenz exposure in Chinese PLWH co-infected with TB. METHOD PLWH were screened according to inclusion and exclusion criteria and divided into HIV group and HIV/TB group. Efavirenz plasma concentration (C0) was determined, dose-adjusted concentration (C0/D) was calculated, and genotypes of CYP2B6 516G>T, 785A>G, and ABCB1 2677G>T, 3435C>T were analyzed. RESULTS 252 PLWH were enrolled, including 75 co-infected with TB and concomitant with rifampicin. Efavirenz C0 and C0/D were both higher in HIV group (1.94 μg/mL, 0.2007 (μg/ml)/(mg/kg/d)) compared with HIV/TB group (1.52 μg/mL, 0.1557 (μg/ml)/(mg/kg/d)) (p = .001). Efavirenz C0/D was significantly higher in patients with variant genotypes of CYP2B6 516G>T and 785A>G (p<.001), and was significantly lower in HIV/TB group compared with HIV group among patients with CYP2B6 516 GG, TT, and 785 AA, AG genotypes (p < .05). CONCLUSION Efavirenz exposure is reduced by co-administration with rifampicin, and related to genetic polymorphisms of CYP2B6.
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Affiliation(s)
- Li Zhang
- Department of Pharmacy, 159397Huashan Hospital Fudan University, Shanghai, People's Republic of China.,Department of Pharmacy, 34748Shanghai Public Health Clinical Center, Shanghai, People's Republic of China
| | - Xianmin Meng
- Department of Pharmacy, 34748Shanghai Public Health Clinical Center, Shanghai, People's Republic of China
| | - Ping Dong
- Department of Pharmacy, 34748Shanghai Public Health Clinical Center, Shanghai, People's Republic of China
| | - Tangkai Qi
- Department of Infectious Disease, 34748Shanghai Public Health Clinical Center, Shanghai, People's Republic of China
| | - Li Liu
- Department of Infectious Disease, 34748Shanghai Public Health Clinical Center, Shanghai, People's Republic of China
| | - Bin Wang
- Department of Pharmacy, 159397Huashan Hospital Fudan University, Shanghai, People's Republic of China
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Eum S, Sayre F, Lee AM, Stingl JC, Bishop JR. Association of CYP2B6 genetic polymorphisms with bupropion and hydroxybupropion exposure: A systematic review and meta-analysis. Pharmacotherapy 2021; 42:34-44. [PMID: 34752647 DOI: 10.1002/phar.2644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 10/16/2021] [Accepted: 10/17/2021] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Bupropion is metabolized to its active metabolite, hydroxybupropion (HB), by the genetically polymorphic cytochrome P450 2B6 (CYP2B6) enzyme. Despite its significant role in bupropion metabolism, the magnitude of the impact of CYP2B6 genotype on the exposure of bupropion has not been quantified. OBJECTIVES A systematic review and meta-analysis was conducted to quantify the association of bupropion and HB exposure with CYP2B6 variant alleles and genotype-defined metabolizer phenotypes. METHODS MEDLINE, EMBASE, Web of Science, Scifinder, PsycINFO, and CENTRAL were screened to identify studies that met the following inclusion criteria (search updated on February 2021): (1) area under the plasma drug concentration-time curve (AUC) of bupropion and/or HB in relation to CYP2B6 genotypes was studied, and (2) study participants were genotyped for common CYP2B6 variant alleles including at least CYP2B6*6. The Newcastle Ottawa Scale was used to assess risk of bias in each included study. The ratio of means (RoM) between CYP2B6 genotype or genotype-defined phenotype groups for bupropion exposure was calculated for each study and combined in a meta-analysis. RESULTS Eleven studies met the inclusion criteria for this systematic review, and 10 (including N = 413 participants) were included in the meta-analysis. All 10 studies involved healthy adult volunteers, where other medications were not allowed. The AUCs of HB and the active moiety (bupropion + HB) were significantly reduced in CYP2B6*6 carriers compared with the non-carriers (HB: RoM 0.77, 95% CI 0.71-0.83; active moiety: RoM 0.81, 95% CI 0.75-0.88). Both CYP2B6 poor and intermediate metabolizers had significantly decreased exposures to HB and the active moiety than normal metabolizers. CONCLUSION The CYP2B6*6 allele and genotype-determined CYP2B6 poor and intermediate metabolizer phenotypes are associated with significantly lower exposures to HB and the total active moiety. The findings of this study suggest opportunities to further study precision dosing strategies for bupropion therapy based on CYP2B6 genotype.
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Affiliation(s)
- Seenae Eum
- Department of Pharmacogenomics, School of Pharmacy, Shenandoah University, Fairfax, Virginia, USA
| | - Franklin Sayre
- Librarian Department, Thompson Rivers University, Kamloops, British Columbia, Canada
| | - Adam M Lee
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Julia C Stingl
- Institute of Clinical Pharmacology, University Hospital of RWTH Aachen, Aachen, Germany
| | - Jeffrey R Bishop
- Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA.,Department of Psychiatry and Behavioral Sciences, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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Marok FZ, Fuhr LM, Hanke N, Selzer D, Lehr T. Physiologically Based Pharmacokinetic Modeling of Bupropion and Its Metabolites in a CYP2B6 Drug-Drug-Gene Interaction Network. Pharmaceutics 2021; 13:331. [PMID: 33806634 PMCID: PMC8001859 DOI: 10.3390/pharmaceutics13030331] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/22/2021] [Accepted: 02/27/2021] [Indexed: 12/22/2022] Open
Abstract
The noradrenaline and dopamine reuptake inhibitor bupropion is metabolized by CYP2B6 and recommended by the FDA as the only sensitive substrate for clinical CYP2B6 drug-drug interaction (DDI) studies. The aim of this study was to build a whole-body physiologically based pharmacokinetic (PBPK) model of bupropion including its DDI-relevant metabolites, and to qualify the model using clinical drug-gene interaction (DGI) and DDI data. The model was built in PK-Sim® applying clinical data of 67 studies. It incorporates CYP2B6-mediated hydroxylation of bupropion, metabolism via CYP2C19 and 11β-HSD, as well as binding to pharmacological targets. The impact of CYP2B6 polymorphisms is described for normal, poor, intermediate, and rapid metabolizers, with various allele combinations of the genetic variants CYP2B6*1, *4, *5 and *6. DDI model performance was evaluated by prediction of clinical studies with rifampicin (CYP2B6 and CYP2C19 inducer), fluvoxamine (CYP2C19 inhibitor) and voriconazole (CYP2B6 and CYP2C19 inhibitor). Model performance quantification showed 20/20 DGI ratios of hydroxybupropion to bupropion AUC ratios (DGI AUCHBup/Bup ratios), 12/13 DDI AUCHBup/Bup ratios, and 7/7 DDGI AUCHBup/Bup ratios within 2-fold of observed values. The developed model is freely available in the Open Systems Pharmacology model repository.
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Affiliation(s)
| | | | | | | | - Thorsten Lehr
- Clinical Pharmacy, Saarland University, 66123 Saarbrücken, Germany; (F.Z.M.); (L.M.F.); (N.H.); (D.S.)
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Fernandes MR, Rodrigues JCG, Maroñas O, Latorre-Pellicer A, Cruz R, Guerreiro JF, Burbano RMR, de Assumpção PP, Ribeiro-Dos-Santos A, Dos Santos SEB, Carracedo A, Dos Santos NPC. Genetic Diversity of Drug-Related Genes in Native Americans of the Brazilian Amazon. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2021; 14:117-133. [PMID: 33519226 PMCID: PMC7837547 DOI: 10.2147/pgpm.s274741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/23/2020] [Indexed: 12/25/2022]
Abstract
Introduction The genetic admixture of the Brazilian population has considerable relevance to the implementation of the principles of pharmacogenomics (PGx), as it may compromise the extrapolation of data obtained in more homogeneous world populations. Purpose This study aims to investigate a panel of 117 polymorphisms in 35 pharmacogenes, which contains label recommendations or clinical evidence by international drug regulatory agencies, in Amazonian Native American populations, and compare the results obtained with continental population data from the 1000 Genomes Project Consortium. Patients and Methods The study population is composed of 109 Native American individuals from three Brazilian Amazon groups. The genotyping of the PGx polymorphisms was performed by allelic discrimination using TaqMan® OpenArray Genotyping with a panel of 120 customized assays on the QuantStudio™ 12K Flex Real-Time PCR System. Results Statistical differences within the Native American populations were observed regarding both genotypes and phenotypes of some genes of the CYP family. The discriminant analysis of principal components (DAPCs) between the NAM group and the continental populations of the 1000 Genomes Project resulted in the clustering of the three Native American populations. Additionally, in general, the NAM group was determined to be closely situated between East Asia, America, and South Asia groups, which enabled us to infer a genetic similarity between these populations. The DAPC analysis further demonstrated that eight polymorphisms and six polymorphisms were more relevant in differentiating the NAM from the continental populations and the NAM populations among themselves, respectively. Conclusion Some investigated polymorphisms show differences among world populations, particularly with populations of European origin, for whom precision medicine protocols are primarily designed. The accumulated knowledge regarding these variations may assist in the design of specific protocols for Native American populations and populations admixed with them.
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Affiliation(s)
- Marianne Rodrigues Fernandes
- Núcleo de Pesquisas em Oncologia, Universidade Federal do Pará, Belém, Pará, Brazil.,Departamento de ensino e pesquisa, Hospital Ophir Loyola, Belém, Pará, Brazil
| | | | - Olalla Maroñas
- Grupo de Medicina Xenómica, Centro Nacional de Genotipado (CEGEN-PRB3), Universidade de Santiago de Compostela, Santiago de Compostela, España
| | - Ana Latorre-Pellicer
- Grupo de Medicina Xenómica, Centro Nacional de Genotipado (CEGEN-PRB3), Universidade de Santiago de Compostela, Santiago de Compostela, España.,Unidad de Genética Clínica y Genómica Funcional, Departamento de Farmacología-Fisiología, Escuela de Medicina, Universidad de Zaragoza, IIS-Aragón, E-50009 Zaragoza, España
| | - Raquel Cruz
- Centro de Investigación Biomédica en Enfermedades Raras (CIBERER), Grupo de Medicina Genómica, CIMUS, Universidad de Santiago de Compostela, Santiago de Compostela, España
| | - João Farias Guerreiro
- Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Rommel Mario Rodriguez Burbano
- Núcleo de Pesquisas em Oncologia, Universidade Federal do Pará, Belém, Pará, Brazil.,Departamento de ensino e pesquisa, Hospital Ophir Loyola, Belém, Pará, Brazil
| | | | - Andrea Ribeiro-Dos-Santos
- Núcleo de Pesquisas em Oncologia, Universidade Federal do Pará, Belém, Pará, Brazil.,Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Sidney Emanuel Batista Dos Santos
- Núcleo de Pesquisas em Oncologia, Universidade Federal do Pará, Belém, Pará, Brazil.,Laboratório de Genética Humana e Médica, Universidade Federal do Pará, Belém, Pará, Brazil
| | - Angel Carracedo
- Grupo de Medicina Xenómica, Centro Nacional de Genotipado (CEGEN-PRB3), Universidade de Santiago de Compostela, Santiago de Compostela, España.,Centro de Investigación Biomédica en Enfermedades Raras (CIBERER), Grupo de Medicina Genómica, CIMUS, Universidad de Santiago de Compostela, Santiago de Compostela, España.,Fundación Pública de Medicina Xenómica, Instituto de Investigación Sanitaria de Santiago de Compostela (FIDIS), Universidade de Santiago de Compostela, Santiago de Compostela, España
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Wang PF, Neiner A, Kharasch ED. Stereoselective Bupropion Hydroxylation by Cytochrome P450 CYP2B6 and Cytochrome P450 Oxidoreductase Genetic Variants. Drug Metab Dispos 2020; 48:438-445. [PMID: 32238417 DOI: 10.1124/dmd.119.090407] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/10/2020] [Indexed: 12/12/2022] Open
Abstract
Bioactivation of the antidepressant and smoking cessation drug bupropion is catalyzed predominantly by CYP2B6. The metabolite hydroxybupropion derived from t-butylhydroxylation is considered to contribute to the antidepressant and smoking-cessation effects of the parent drug. Bupropion hydroxylation is the canonical in vitro and in vivo probe for CYP2B6 activity. P450 also requires obligate partnership with P450 oxidoreductase (POR). Human CYP2B6 and POR genes are highly polymorphic. Some CYP2B6 variants affect bupropion disposition. This investigation evaluated the influence of several human CYP2B6 and POR genetic variants on stereoselective bupropion metabolism, using an insect cell coexpression system containing CYP2B6, POR, and cytochrome b 5 Based on intrinsic clearances (Clints), relative activities for S,S-hydroxybupropion formation were in the order CYP2B6.4 > CYP2B6.1 > CYP2B6.17 > CYP2B6.5 > CYP2B6.6 ≈ CYP2B6.26 ≈ CYP2B6.19 > CYP2B6.7 > CYP2B6.9 > > CYP2B6.16 and CYP2B6.18; relative activities for R,R-hydroxybupropion formation were in the order CYP2B6.17 > CYP2B6.4 > CYP2B6.1 > CYP2B6.5 ≈ CYP2B6.19 ≈ CYP2B6.26 > CYP2B6.6 > CYP2B6.7 ≈ CYP2B6.9 > > CYP2B6.16 and CYP2B6.18. Bupropion hydroxylation was not influenced by POR variants. CYP2B6-catalyzed bupropion hydroxylation is stereoselective. Though Vmax and Km varied widely among CYP2B6 variants, stereoselectivity was preserved, reflected by similar Clint(S,S-hydroxybupropion)/Clint(R,R-hydroxybupropion) ratios (1.8-2.9), except CYP2B6.17, which was less enantioselective. Established concordance between human bupropion hydroxylation in vitro and in vivo, together with these new results, suggests additional CYP2B6 variants may influence human bupropion disposition. SIGNIFICANCE STATEMENT: Bupropion pharmacokinetics, metabolism, and clinical effects are affected by the CYP2B6*6 polymorphism. Other expressed CYP2B6 polymorphisms had diminished (*5, *6, *7, *9, *19, *26) or defective (*16, *18) in vitro bupropion hydroxylation. P450 oxidoreductase genetic variants had no effect on metabolism, suggesting no clinical consequence of this polymorphism. These CYP2B6 polymorphisms may portend diminished in vivo bupropion hydroxylation and predict additional clinically important variant alleles.
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Affiliation(s)
- Pan-Fen Wang
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (P.-F.W., E.D.K.) and Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri (A.N.)
| | - Alicia Neiner
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (P.-F.W., E.D.K.) and Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri (A.N.)
| | - Evan D Kharasch
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina (P.-F.W., E.D.K.) and Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri (A.N.)
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Stereoselective Ketamine Metabolism by Genetic Variants of Cytochrome P450 CYP2B6 and Cytochrome P450 Oxidoreductase. Anesthesiology 2019; 129:756-768. [PMID: 30085944 DOI: 10.1097/aln.0000000000002371] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
WHAT WE ALREADY KNOW ABOUT THIS TOPIC WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Human ketamine N-demethylation to norketamine in vitro at therapeutic concentrations is catalyzed predominantly by the cytochrome P4502B6 isoform (CYP2B6). The CYP2B6 gene is highly polymorphic. CYP2B6.6, the protein encoded by the common variant allele CYP2B6*6, exhibits diminished ketamine metabolism in vitro compared with wild-type CYP2B6.1. The gene for cytochrome P450 oxidoreductase (POR), an obligatory P450 coenzyme, is also polymorphic. This investigation evaluated ketamine metabolism by genetic variants of human CYP2B6 and POR. METHODS CYP2B6 (and variants), POR (and variants), and cytochrome b5 (wild-type) were coexpressed in a cell system. All CYP2B6 variants were expressed with wild-type POR and b5. All POR variants were expressed with wild-type CYP2B6.1 and b5. Metabolism of R- and S-ketamine enantiomers, and racemic RS-ketamine to norketamine enantiomers, was determined using stereoselective high-pressure liquid chromatography-mass spectrometry. Michaelis-Menten kinetic parameters were determined. RESULTS For ketamine enantiomers and racemate, metabolism (intrinsic clearance) was generally wild-type CYP2B6.1 > CYP2B6.4 > CYP2B6.26, CYP2B6.19, CYP2B6.17, CYP2B6.6 > CYP2B6.5, CYP2B6.7 > CYP2B6.9. CYP2B6.16 and CYP2B6.18 were essentially inactive. Activity of several CYP2B6 variants was less than half that of CYP2B6.1. CYP2B6.9 was 15 to 35% that of CYP2B6.1. The order of metabolism was wild-type POR.1 > POR.28, P228L > POR.5. CYP2B6 variants had more influence than POR variants on ketamine metabolism. Neither CYP2B6 nor POR variants affected the stereoselectivity of ketamine metabolism (S > R). CONCLUSIONS Genetic variants of CYP2B6 and P450 oxidoreductase have diminished ketamine N-demethylation activity, without affecting the stereoselectivity of metabolism. These results suggest candidate genetic polymorphisms of CYP2B6 and P450 oxidoreductase for clinical evaluation to assess consequences for ketamine pharmacokinetics, elimination, bioactivation, and therapeutic effects.
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Kharasch ED, Crafford A. Common Polymorphisms of CYP2B6 Influence Stereoselective Bupropion Disposition. Clin Pharmacol Ther 2018; 105:142-152. [PMID: 29756345 DOI: 10.1002/cpt.1116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/08/2018] [Indexed: 12/12/2022]
Abstract
Bupropion hydroxylation is a bioactivation and metabolic pathway, and the standard clinical CYP2B6 probe. This investigation determined the influence of CYP2B6 allelic variants on clinical concentrations and metabolism of bupropion enantiomers. Secondary objectives evaluated the influence of CYP2C19 and P450 oxidoreductase variants. Healthy volunteers in specific cohorts (CYP2B6*1/*1, CYP2B6*1/*6, CYP2B6*6/*6, and also CYP2B6*4 carriers) received single-dose oral bupropion. Plasma and urine bupropion and hydroxybupropion was quantified. Subjects were also genotyped for CYP2C19 and P450 oxidoreductase variants. Hydroxylation of both bupropion enantiomers, assessed by plasma hydroxybupropion/bupropion AUC ratios and urine hydroxybupropion formation clearances, was lower in CYP2B6*6/*6 but not CYP2B6*1/*6 compared with CYP2B6*1/*1 genotypes, and numerically greater in CYP2B6*4 carriers. CYP2C19 and P450 oxidoreductase variants did not influence bupropion enantiomers hydroxylation or plasma concentrations. The results show that clinical hydroxylation of both bupropion enantiomers was equivalently influenced by CYP2B6 allelic variation. CYP2B6 polymorphisms affect S-bupropion bioactivation, which may affect therapeutic outcomes.
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Affiliation(s)
- Evan D Kharasch
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, Missouri, USA.,Center for Clinical Pharmacology, St. Louis College of Pharmacy and Washington University in St. Louis, St. Louis, Missouri, USA
| | - Amanda Crafford
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri, USA
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