- Use of any of the following in the 14 days prior to enrollment: ketoconazole, itraconazole, fluconazole, erythromycin, clarithromycin, troleandomycin, indinavir, nelfinavir, ritonavir, fluvoxamine, saquinavir phenytoin, carbamazepine, barbiturates, rifampin, St. John's Wort, and glucocorticoids.