6. Use of drugs or foods that are known potent CYP3A4 inhibitors, including but not limited to amprenavir, atazanavir, clarithromycin, delavirdine, diltiazem, erythromycin, indinavir, itraconazole, ketoconazole, miconazole, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, troleandomycin, verapamil, voriconazole, and grapefruit or grapefruit juice.