- CYP3A4 inhibitors: patients chronically receiving drugs that are known potent CYP3A4 inhibitors within 7 days prior to study enrollment, including but not limited to ketoconazole, itraconazole, clarithromycin, erythromycin, ritonavir, indinavir, nelfinavir, saquinavir, delavirdine, nefazodone, diltiazem, verapamil, and grapefruit juice are not eligible; the topical use of these medications (if applicable), e.g. 2% ketoconazole cream, is allowed