Verapamil vs Amlodipine: Uses and Contraindications
Amlodipine is generally preferred over verapamil for most patients requiring a calcium channel blocker due to its better safety profile, fewer contraindications, and once-daily dosing convenience.
Mechanism of Action Differences
Both medications are calcium channel blockers (CCBs) but work differently:
Verapamil (non-dihydropyridine CCB):
- Prominent effects on AV node conduction and sinus node function
- Moderate peripheral vasodilation
- Significant negative inotropic effects on cardiac contractility 1
Amlodipine (dihydropyridine CCB):
Clinical Uses
Shared Indications
- Hypertension
- Chronic stable angina
Verapamil-Specific Uses
- Supraventricular tachyarrhythmias (including atrial fibrillation rate control)
- Variant angina (vasospastic angina)
- Hypertrophic cardiomyopathy 1
Amlodipine-Specific Uses
- Vasospastic (Prinzmetal's) angina
- Documented coronary artery disease for event reduction
- Can be used in patients with heart failure due to systolic dysfunction (NYHA class II-III) 3
Contraindications
Verapamil Contraindications (more restrictive)
- Severe left ventricular dysfunction
- Hypotension (systolic BP <90 mmHg) or cardiogenic shock
- Sick sinus syndrome (except with functioning pacemaker)
- Second or third-degree AV block (except with functioning pacemaker)
- Atrial flutter/fibrillation with accessory bypass tract (e.g., WPW syndrome)
- Known hypersensitivity to verapamil 4
Amlodipine Contraindications (fewer)
- Known sensitivity to amlodipine 3
Comparative Efficacy and Safety
Blood Pressure Control
- Both are effective for hypertension
- Amlodipine provides better 24-hour blood pressure control with once-daily dosing 5, 6
Heart Failure Considerations
- Verapamil should be avoided in patients with pulmonary edema or severe LV dysfunction 1
- Amlodipine is better tolerated in patients with mild-to-moderate heart failure 1, 3
Side Effect Profiles
- Verapamil: Constipation (especially in elderly), bradycardia, AV block, worsening heart failure, hypotension 1
- Amlodipine: Peripheral edema (most common), headache, flushing 2, 3
Special Populations
Patients with Coronary Artery Disease
- Amlodipine has demonstrated favorable outcomes in reducing hospitalizations for angina and revascularization procedures in patients with documented CAD (CAMELOT trial) 3
Patients with Heart Failure with Preserved Ejection Fraction
- Amlodipine may be superior to verapamil for improving left ventricular diastolic function in patients with hypertension and heart failure with preserved ejection fraction 7
Clinical Decision Algorithm
For hypertension with no comorbidities: Either agent is appropriate, but amlodipine offers simpler once-daily dosing
For patients with:
- Heart failure or LV dysfunction → Choose amlodipine (verapamil contraindicated)
- Atrial fibrillation requiring rate control → Choose verapamil
- Conduction disorders → Choose amlodipine (verapamil may worsen AV block)
- Coronary artery disease → Amlodipine has better evidence for event reduction
For elderly patients: Amlodipine generally preferred (verapamil causes more constipation)
Common Pitfalls to Avoid
- Never use rapid-release, short-acting dihydropyridines (like immediate-release nifedipine) without beta-blocker coverage due to risk of reflex tachycardia 1
- Avoid combining verapamil with beta-blockers due to risk of severe bradycardia and heart block
- Don't use verapamil in patients taking ivabradine (risk of severe bradycardia due to shared metabolism via CYP3A4) 1
- Monitor for peripheral edema with amlodipine, which may be misinterpreted as worsening heart failure
In conclusion, while both medications are effective calcium channel blockers, amlodipine offers advantages of fewer contraindications, once-daily dosing, and better tolerability in patients with mild-to-moderate heart failure, making it the preferred option in most clinical scenarios.