Major
Propranolol × Verapamil
Non-selective beta blocker×Non-dihydropyridine calcium channel blocker
Mechanism
Non-dihydropyridine calcium channel blocker (verapamil) + non-selective beta-blocker (propranolol) – marked additive bradycardia, AV block, negative inotropic effect. Symptomatic AV block and asystole have been reported.
Symptoms
Bradycardia (heart rate below 50/min), dizziness, syncope. ECG: first- to second-degree AV block. Older patients: fall risk.
Management
Avoid the combination. For atrial fibrillation rate control: propranolol + digoxin (without verapamil) or verapamil with propranolol withdrawn. In heart failure, use a selective beta-blocker (bisoprolol) or carvedilol.