 - Cytochrome P450 CYP3A4 active agents: Must not be taking any of the following potent CYP3A4 inducers or inhibitors within 1 week prior to study entry: azole antifungals such as fluconazole, voriconazole, itraconazole, ketoconazole, rifampin, phenytoin, phenobarbitol, carbamazepine, grapefruit juice and St. Johns wort. 