Dataset Information

Fatal methadone toxicity: potential role of CYP3A4 genetic polymorphism.

ABSTRACT: Methadone is difficult to administer as a therapeutic agent because of a wide range of interindividual pharmacokinetics, likely due to genetic variability of the CYP450 enzymes responsible for metabolism to its principal metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP). CYP3A4 is one of the primary CYP450 isoforms responsible for the metabolism of methadone to EDDP in humans. The purpose of this study was to evaluate the role of CYP3A4 genetic polymorphisms in accidental methadone fatalities. A study cohort consisting of 136 methadone-only and 92 combined methadone/benzodiazepine fatalities was selected from cases investigated at the West Virginia and Kentucky Offices of the Chief Medical Examiner. Seven single nucleotide polymorphisms (SNPs) were genotyped within the CYP3A4 gene. Observed allelic and genotypic frequencies were compared with expected frequencies obtained from The National Center for Biotechnology Information dbSNP database. SNPs rs2242480 and rs2740574 demonstrated an apparent enrichment within the methadone-only overdose fatalities compared with the control group and the general population. This enrichment was not apparent in the methadone/benzodiazepine cases for these two SNPs. Our findings indicate that there may be two or more SNPs on the CYP3A4 gene that cause or contribute to the methadone poor metabolizer phenotype.

SUBMITTER: Richards-Waugh LL

PROVIDER: S-EPMC4229888 | biostudies-literature | 2014 Oct

REPOSITORIES: biostudies-literature

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Fatal methadone toxicity: potential role of CYP3A4 genetic polymorphism.

Richards-Waugh Lauren L LL Primerano Donald A DA Dementieva Yulia Y Kraner James C JC Rankin Gary O GO

Journal of analytical toxicology 20141001 8

Methadone is difficult to administer as a therapeutic agent because of a wide range of interindividual pharmacokinetics, likely due to genetic variability of the CYP450 enzymes responsible for metabolism to its principal metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP). CYP3A4 is one of the primary CYP450 isoforms responsible for the metabolism of methadone to EDDP in humans. The purpose of this study was to evaluate the role of CYP3A4 genetic polymorphisms in accidental metha ...[more]

PMID: 25217544

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Project description:BackgroundDue to the COVID-19 pandemic, the Substance Abuse and Mental Health Services Administration (SAMHSA) has relaxed restrictions on methadone treatment in the United States. There is concern that the relaxation may increase fatal overdose rates. This study examines opioid treatment program (OTP) changes to methadone treatment during COVID-19 and changes in fatal methadone-involved overdose rates in Connecticut.MethodsFrom July 8th to August 18th, 2020, we conducted a comprehensive state-wide survey of all eight OTPs that dispense methadone in Connecticut to examine programmatic changes during COVID-19. We also analyzed state-level data on confirmed accidental opioid-involved deaths to assess if relaxation of take-home dosing restrictions and in-person attendance requirements correlated with increased methadone-involved fatal overdose rates.ResultsOTPs reported implementing multiple changes to methadone treatment in response to the COVID-19 pandemic. The percent of patients receiving 28-day take-home doses increased from 0.1% to 16.8%, 14-day take-home doses increased from 14.2% to 26.8%, and the percent receiving one or no take-home doses decreased from 37.5% to 9.6%. Monthly or more frequent drug testing decreased from 15% to 4.6% and 75.2% of individual counseling for methadone patients transitioned to telehealth. However, changes to methadone treatment varied considerably by program. OTP providers said restrictions on methadone should be relaxed and increases in take-home dosing as well as telehealth should be continued in non-pandemic situations. Methadone-involved fatalities relative to other opioid-involved fatalities did not increase in Connecticut following changes in OTP practices.ConclusionsConnecticut OTPs relaxed methadone treatment requirements during COVID-19. Since relaxing restrictions on methadone treatment has not increased fatal overdoses, we recommend that the reductions in-person dosing and attendance requirements implemented during the COVID-19 pandemic should be continued and made permanent.

Project description:The aim of this study was to 1) investigate the effects of 27 CYP3A4 variants on the metabolism of osimertinib and 2) study the interactions between osimertinib and others as well as the underlying mechanism. A recombinant human CYP3A4 enzymatic incubation system was developed and employed to determine the kinetic profile of CYP3A4 variants. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was applied to detect the concentration of the main metabolite, AZ5104. The results demonstrated that the relative clearance rates of CYP3A4.19, 10, 18, 5, 16, 14, 11, 2, 13, 12, 7, 8, and 17 in catalyzing osimertinib were significantly reduced to a minimum of 25.68% compared to CYP3A4.1, while those of CYP3A4.29, 32, 33, 28, 15, 34, and 3 were obviously enhanced, ranging from 114.14% to 284.52%. The activities of the remaining variants were almost equal to those of CYP3A4.1. In addition, 114 drugs were screened to determine the potential interaction with osimertinib based on the rat liver microsome (RLM) reaction system. Sixteen of them inhibited the production of AZ5104 to 20% or less, especially proton pump inhibitors, among which the IC50 of rabeprazole was 6.49 ± 1.17 μM in RLM and 20.39 ± 2.32 μM in human liver microsome (HLM), with both following competitive and non-competitive mixed mechanism. In an in vivo study, Sprague-Dawley (SD) rats were randomly divided into groups, with six animals per group, receiving osimertinib with or without rabeprazole, omeprazole, and lansoprazole. We found that the AUC(0-t), AUC(0-∞), and Cmax of osimertinib decreased significantly after co-administration with rabeprazole orally, but they increased remarkably when osimertinib was administered through intraperitoneal injection. Taken together, our data demonstrate that the genetic polymorphism and proton pump inhibitors remarkably influence the disposition of osimertinib, thereby providing basic data for the precise application of osimertinib.

Project description:Background and objectiveThe association between the CYP3A4*1B single nucleotide polymorphism (SNP) and tacrolimus pharmacokinetics in different studies is controversial. Therefore, a meta-analysis was employed to evaluate the correlation between the CYP3A4*1B genetic polymorphism and tacrolimus pharmacokinetics at different post-transplantation times in adult renal transplant recipients.MethodsStudies evaluating the CYP3A4*1B genetic polymorphism and tacrolimus pharmacokinetics were retrieved through a systematical search of Embase, PubMed, the Cochrane Library, ClinicalTrials.gov and three Chinese literature databases (up to Sept. 2014). The pharmacokinetic parameters (weight-adjusted tacrolimus daily dose and tacrolimus trough concentration/weight-adjusted tacrolimus daily dose ratio) were extracted, and the meta-analysis was performed using Stata 12.1.ResultsSeven studies (involving 1182 adult renal transplant recipients) were included in this meta-analysis. For the weight-adjusted tacrolimus daily dose, in all included renal transplant recipients (European & Indian populations), CYP3A4*1/*1 recipients required a significantly lower weight-adjusted tacrolimus daily dose than did CYP3A4*1B carriers at 7 days (WMD -0.048; 95% CI -0.083 ~ -0.014), 6 months (WMD -0.058; 95% CI -0.081 ~ -0.036) and 12 months (WMD - 0.061; 95% CI -0.096 ~ -0.027) post-transplantation. In light of the heterogeneity, the analysis was repeated after removing the only study in an Indian population, and CYP3A4*1/*1 European recipients (mostly Caucasian) required a lower weight-adjusted tacrolimus daily dose within the first year post-transplantation. The tacrolimus trough concentration/weight-adjusted tacrolimus daily dose ratio (C0/Dose ratio) was significantly higher in CYP3A4*1/*1 recipients than in CYP3A4*1B carriers at 6 months (WMD 52.588; 95% CI 22.387 ~ 82.789) and 12 months (WMD 62.219; 95% CI 14.218 ~ 110.221) post-transplantation. When the only study in an Indian population was removed to examine European recipients (mostly Caucasian), the significant difference persisted at 1 month, 6 months and 12 months post-transplantation.ConclusionBased on our meta-analysis, the CYP3A4*1B genetic polymorphism affects tacrolimus dose requirements and tacrolimus trough concentration/weight-adjusted tacrolimus daily dose ratio within the first year post-transplantation in adult renal transplant recipients, especially in European recipients (mostly Caucasian).

Dataset Information

Fatal methadone toxicity: potential role of CYP3A4 genetic polymorphism.

Publications

Fatal methadone toxicity: potential role of CYP3A4 genetic polymorphism.

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