 - No concurrent use of strong CYP3A4 inhibitor e.g., ketoconazole, voriconazole, grapefruit or inducers e.g., phenytoin, carbamazepine, phenobarbital, St. Johns Wort Hypericum perforatum, dexamethasone at a dose of greater than 16 mg daily, or rifampin rifampicin, andor rifabutin. 2 week washout period before enrollment required if any of strong inducer or inhibitors used except for dexamethasone, dose needs to be 16mg or less daily. Appendix H 