Effect of patient genetics on etonogestrel pharmacokinetics when combined with efavirenz or nevirapine ART.
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ABSTRACT: BACKGROUND:We previously demonstrated that etonogestrel concentrations were 82% lower in women using etonogestrel contraceptive implants plus efavirenz-based ART compared with women not receiving ART. OBJECTIVES:To investigate the genetic contribution to this previously observed drug-drug interaction through studying SNPs in genes known to be involved in efavirenz, nevirapine or etonogestrel metabolism in the same group of women. PATIENTS AND METHODS:Here, we present a secondary analysis evaluating SNPs involved in efavirenz, nevirapine and etonogestrel metabolism and associated etonogestrel pharmacokinetics among 57 women, 19 not receiving ART (control group), 19 receiving efavirenz- (600?mg daily) based ART and 19 receiving nevirapine- (200?mg twice daily) based ART. Associations between patient genotype and etonogestrel pharmacokinetic parameters were determined through univariate and multivariate linear regression. This study was registered at clinicaltrials.gov (NCT02082652). RESULTS:Within the control group, CYP2B6 983?T>C was associated with 27% higher etonogestrel Cmax and 28% higher AUC0-24weeks. In the efavirenz group CYP2B6 516?G>T was associated with 43% lower etonogestrel Cmin and 34% lower AUC0-24weeks. For participants receiving nevirapine, NR1I2 63396?C>T was associated with 39% lower etonogestrel Cmin and 37% lower AUC0-24weeks. CONCLUSIONS:This study demonstrates the influence of pharmacogenetics on the extent of drug-drug interactions between etonogestrel and efavirenz- or nevirapine-based ART. Efavirenz plus the etonogestrel contraceptive implant results in a detrimental drug-drug interaction irrespective of patient genetics, which is worsened in women possessing variant alleles for these CYP2B6 SNPs.
SUBMITTER: Neary M
PROVIDER: S-EPMC6753484 | biostudies-literature | 2019 Oct
REPOSITORIES: biostudies-literature
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