Agents inhibiting CYP3A metabolism Agents such as protease inhibitors (indinavir, nelfinavir, ritonavir), antifungals (e. g., itraconazole, ketoconazole, voriconazole), calcium channel blockers (e. g., diltiazem, verapamil), macrolide antibiotics (e. g., clarithromycin, erythromycin), and cimetidine, grapefruit juice, aprepitant, fluvoxamine and nefazodone are strong CYP3A4 inhibitors and may increase blood concentrations of the active moieties, temsirolimus and its metabolite, sirolimus.