Cytochrome P450 2B6 516G→T is associated with plasma concentrations of nevirapine at both 200 mg twice daily and 400 mg once daily in an ethnically diverse population

Objectives The aim of the study was to characterize the impact of the cytochrome P450 2B6 (CYP2B6), CYP3A4, CYP3A5 and ATP‐binding cassette sub‐family B member 1 (ABCB1) polymorphisms on nevirapine plasma concentrations. Methods A total of 104 patients (82% male; 26% non‐Caucasian) were genotyped for eight single nucleotide polymorphisms at four loci (CYP2B6, CYP3A4, CYP3A5 and MDR1). Nevirapine plasma concentrations were determined using high‐performance liquid chromatography. Results Non‐Caucasian ethnicity [5609 ng/mL (n=27) for non‐Caucasians vs. 3771 ng/mL (n=77) for Caucasians; P