Does Amlodipine Besylate Cause Bradycardia?
Amlodipine besylate does not cause bradycardia at therapeutic doses. Unlike non-dihydropyridine calcium channel blockers (verapamil, diltiazem), amlodipine has minimal effects on cardiac conduction tissue and does not affect sinoatrial nodal function or atrioventricular conduction 1.
Mechanism and Electrophysiologic Effects
Amlodipine is a dihydropyridine calcium channel blocker that acts primarily as a peripheral arterial vasodilator, with no significant negative chronotropic effects 1.
The FDA drug label explicitly states that amlodipine does not change sinoatrial nodal function or atrioventricular conduction in intact animals or humans 1.
In clinical studies where amlodipine was administered with beta-blockers to patients with hypertension or angina, no adverse effects on electrocardiographic parameters were observed, and no higher degrees of AV blocks occurred 1.
Chronic oral administration of amlodipine in clinical trials did not lead to clinically significant changes in heart rate, unlike the acute intravenous administration which may transiently increase heart rate 1.
Contrast with Non-Dihydropyridine Calcium Channel Blockers
Verapamil is contraindicated in pulmonary arterial hypertension specifically because of its tendency to cause bradycardia, along with its negative inotropic effects 2.
Diltiazem may lower heart rate and is noted to cause bradycardia more than other calcium channel blockers 2.
Caution should be exercised when combining non-dihydropyridine calcium channel blockers (verapamil, diltiazem) with beta-blockers due to risk of bradycardia and AV block, but this concern does not apply to amlodipine 2.
Bradycardia Only Occurs in Overdose Situations
Bradycardia with amlodipine is documented only in massive overdose cases, not with therapeutic dosing 3, 4, 5.
In a case report of a patient who ingested 250 mg of amlodipine (50 tablets of 5 mg), refractory bradycardia occurred with a heart rate of 45 bpm and required isoproterenol infusion for treatment 3.
Combined overdose of amlodipine with atenolol (a beta-blocker) causes severe bradycardia and cardiovascular collapse, but this represents the additive effect of the beta-blocker, not amlodipine alone 4, 5.
Clinical Implications
When evaluating a patient with bradycardia, focus on beta-blockers, non-dihydropyridine calcium channel blockers (diltiazem, verapamil), and digoxin as causative agents 6.
Do not discontinue amlodipine in patients presenting with bradycardia, as it is not the causative agent 6.
Amlodipine can be safely combined with beta-blockers without concern for additive bradycardic effects, as demonstrated in multiple clinical trials 1.
The typical hemodynamic response to therapeutic amlodipine is vasodilation with either no change in heart rate or a slight reflex tachycardia, not bradycardia 1, 7.