Other antihypertensives (additive BP lowering), nitrates, alpha-blockers, PDE5 inhibitors (e.g., sildenafil) (risk of hypotension), strong CYP3A4 inhibitors (e.g., clarithromycin, ketoconazole, ritonavir) (increase amlodipine levels), CYP3A4 inducers (e.g., rifampicin, carbamazepine, phenytoin) (reduce effect), simvastatin (limit simvastatin dose; increased statin exposure), tacrolimus/cyclosporine (may increase levels—monitor), grapefruit juice (may increase levels in some patients)