Interactions may occur with drugs that inhibit the cytochrome P450 isoenzyme CYP3A4 including ciclosporin, itraconazole, ketoconazole, erythromycin, clarithromycin, telithromycin, HIV-protease inhibitors, nefazodone, danazol, amiodarone and verapamil; there may also be similar interaction with grapefruit juice.