Major
Amlodipine × Verapamil
Calcium channel blockers (dihydropyridines)×Non-dihydropyridine calcium channel blocker
Mechanism
Dual calcium channel blockade: amlodipine is a dihydropyridine blocker, verapamil is non-dihydropyridine. Additive hypotension, bradycardia, AV block risk.
Symptoms
Blood pressure drop, dizziness, syncope. Bradycardia, ECG first- to second-degree AV block. Older patients: fall risk.
Management
Avoid the combination. In hypertension, choose one calcium channel blocker (amlodipine or verapamil). For difficult hypertension, ACE-I + amlodipine + diuretic (without verapamil) or ACE-I + verapamil.