Effect of fentanyl on the activity of hepatic CYP3A4 and ABCB1 ATPase.

Activity of hepatic CYP3A4 was examined from: (A) human CYP3A4 ectopic expressing insect membranes, (B) human hepatic microsomes and (C) mice hepatic microsomes. Activity of (A, B) was inhibited by less than 20%, and the activity of (C) was significantly inhibited over 40% in present of 20 μM fentanyl with three wells of ketoconazole as positive control inhibited almost 95% of activity of hepatic microsome (C) (data not shown). ABCB1 ATPase assays (D) were performed according to the instruction of Pgp-Glo™ Assay Systems. Data are shown as mean±SD, n = 3.