- Use of strong inhibitors of CYP3A4 (eg, ketoconazole, itraconazole, clarithromycin, ritonavir, indinavir, nelfinavir, nefazodone and saquinavir) and strong inducers of CYP3A4 (eg, rifampin) are not permitted from Day -14 of Cycle 1 and for the duration of the study.