- There is a potential drug interaction when abiraterone is concomitantly used with a cytochrome P450 family 2, subfamily D, polypeptide 6 (CYP2D6) substrate narrow therapeutic index (e.g., thioridazine, dextromethorphan), or strong cytochrome P450 family 3, subfamily A, polypeptide 4 [CYP3A4] inhibitors (e.g., atazanavir, erythromycin, indinavir, itraconazole, Ketoconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, and voriconazole) or strong inducers (e.g., carbamazepine, phenobarbital, phenytoin, rifabutin, rifampin, rifapentine); caution should be used when patients are on one of these drugs