2. increased risk of bradycardia, and the associated therapy with a strong cytochrome P-450 inhibitors (anti-retroviral agents, antifungal agents and some antibiotics eg. Indinavir, Nelfinavir, Lopinavir, Ritonavir, Itraconazole, Ketoconazole, Voriconazole, Clarithromycin, Telithormycin)