Influence of efavirenz on CAR target gene expression in human PBMCs in vitro. PBMCs were isolated and treated with 10 μmol/l efavirenz in vitro. After 48 h of incubation, the cells were harvested, and the expression levels of known target genes were determined by means of semiquantitative PCR. The analysis showed significant induction of CYP2B6, ABCB1, and UGT1A1. Expression profiles of efavirenz in primary human hepatocytes served as positive controls. CAR, constitutive androstane receptor; n.a., not applicable; PBMC, peripheral blood mononuclear cell.