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ABSTRACT: Objective
In AIDS Clinical Trials Group study A5375, a pharmacokinetic trial of levonorgestrel emergency contraception, double-dose levonorgestrel (3 mg, versus standard dose 1.5 mg) offset the induction effects of efavirenz or rifampin on plasma levonorgestrel exposure over 8 h post-dose (AUC 0-8h ). We characterized the pharmacogenetics of these interactions.Methods
Cisgender women receiving efavirenz- or dolutegravir-based HIV therapy, or on isoniazid-rifampin for tuberculosis, were followed after a single oral dose of levonorgestrel. Linear regression models, adjusted for BMI and age, characterized associations of CYP2B6 and NAT2 genotypes (which affect plasma efavirenz and isoniazid exposure, respectively) with levonorgestrel pharmacokinetic parameters.Results
Of 118 evaluable participants, 17 received efavirenz/levonorgestrel 1.5 mg, 35 efavirenz/levonorgestrel 3 mg, 34 isoniazid-rifampin/levonorgestrel 3 mg, and 32 (control group) dolutegravir/levonorgestrel 1.5 mg. There were 73 Black and 33 Asian participants. Regardless of genotype, women on efavirenz and isoniazid-rifampin had higher levonorgestrel clearance. In the efavirenz/levonorgestrel 3 mg group, CYP2B6 normal/intermediate metabolizers had levonorgestrel AUC 0-8h values similar to controls, while CYP2B6 poor metabolizers had AUC 0-8h values of 40% lower than controls. In the isoniazid-rifampin group, NAT2 rapid/intermediate acetylators had levonorgestrel AUC 0-8h values similar to controls, while NAT2 slow acetylators had AUC 0-8h values 36% higher than controls.Conclusion
CYP2B6 poor metabolizer genotypes exacerbate the efavirenz-levonorgestrel interaction, likely by increased CYP3A induction with higher efavirenz exposure, making the interaction more difficult to overcome. NAT2 slow acetylator genotypes attenuate the rifampin-levonorgestrel interaction, likely by increased CYP3A inhibition with higher isoniazid exposure.
SUBMITTER: Agyemang N
PROVIDER: S-EPMC10309098 | biostudies-literature | 2023 Aug
REPOSITORIES: biostudies-literature
Agyemang Nana N Scarsi Kimberly K KK Baker Paxton P Smeaton Laura M LM Podany Anthony T AT Olefsky Maxine M Woolley Elizabeth E Barr Elizabeth E Pham Michelle M Mawlana Sajeeda S Supparatpinyo Khuanchai K Gatechompol Sivaporn S Jalil Emilia M EM Gadama Luis L Badal-Faesen Sharlaa S Van Schalkwyk Marije M Kayama Cecelia C Belaunzaran-Zamudio Pablo F PF Godfrey Catherine C Cohn Susan E SE Mngqibisa Rosie R Haas David W DW
Pharmacogenetics and genomics 20230612 6
<h4>Objective</h4>In AIDS Clinical Trials Group study A5375, a pharmacokinetic trial of levonorgestrel emergency contraception, double-dose levonorgestrel (3 mg, versus standard dose 1.5 mg) offset the induction effects of efavirenz or rifampin on plasma levonorgestrel exposure over 8 h post-dose (AUC 0-8h ). We characterized the pharmacogenetics of these interactions.<h4>Methods</h4>Cisgender women receiving efavirenz- or dolutegravir-based HIV therapy, or on isoniazid-rifampin for tuberculosis ...[more]