Drug metabolism may be affected w/ inducers or inhibitors of CYP3A4. Increased clearance, & plasma conc may be decreased w/ CYP3A4 inducers (eg, phenytoin, barbiturates, primidone, carbamazepine, rifampicin; oxcarbazepine, topiramate, felbamate, griseofulvin); NNRTIs (eg, nevirapine, efavirenz); St. John's wort (
Hypericum perforatum). Plasma conc may be increased w/ strong & moderate CYP3A4 inhibitors eg, azole antifungals (eg, ketoconazole, itraconazole, voriconazole, fluconazole), macrolides (eg, clarithromycin, erythromycin), diltiazem, verapamil; antacids (eg, cimetidine, ranitidine); grapefruit juice. Plasma conc may be increased/decreased w/ HIV/HCV PIs (eg, ritonavir, saquinavir, indinavir, nelfinavir, boceprevir).