- Participants currently receiving zidovudine, or strong CYP3A4 inhibitors (e.g. cobicistat (currently only in Stribild® or ritonavir boosted antiretroviral regimens), ketoconazole, itraconazole, erythromycin, clarithromycin, dexamethasone, phenobarbital, rifampin, phenytoin, carbamazepine, rifabutin, rifapentine, St John's Wort, tacrolimus, cyclosporine, oral contraceptives, warfarin, docetaxel, sirolimus, or other strong inhibitors or inducers of CYP3A4 or substrates of CYP3A4 that have a narrow therapeutic margin