Best Calcium Channel Blocker for Angina
Amlodipine is the preferred calcium channel blocker for treating angina due to its once-daily dosing, sustained 24-hour efficacy, and favorable safety profile compared to other CCBs. 1
Types of Calcium Channel Blockers and Their Effects
Calcium channel blockers (CCBs) are classified into three main categories:
Dihydropyridines (e.g., amlodipine, nifedipine, felodipine)
- Highly selective for vascular L-type calcium channels
- Potent peripheral vasodilation
- Minimal direct effects on cardiac conduction
- May cause reflex tachycardia
Benzothiazepines (e.g., diltiazem)
- Moderate vasodilation
- Moderate negative chronotropic and dromotropic effects
- Slows AV conduction
Phenylalkylamines (e.g., verapamil)
- Strong negative chronotropic and dromotropic effects
- Moderate vasodilation
- Significant slowing of AV conduction 2
Evidence Supporting Amlodipine for Angina
Amlodipine demonstrates several advantages for angina treatment:
- Proven efficacy: FDA-approved for chronic stable angina with significant increases in exercise time (12.8% increase with 10mg dose) 1
- Vasospastic angina: Effectively decreases angina attacks by approximately 4/week compared to placebo 1
- Long duration of action: Once-daily dosing improves compliance 2
- Cardiovascular outcomes: In the CAMELOT trial, amlodipine reduced hospitalization for angina by 42% and coronary revascularization by 27% compared to placebo 1
- Safety profile: Does not significantly affect heart rate or cause negative inotropic effects at therapeutic doses 1, 3
Comparison with Other CCBs
When comparing different calcium channel blockers:
- Amlodipine vs. Diltiazem: Amlodipine's once-daily dosing offers better compliance compared to multiple daily doses of diltiazem, while providing comparable antianginal efficacy 3
- Dihydropyridines vs. Non-dihydropyridines: Non-dihydropyridines (verapamil, diltiazem) have stronger negative chronotropic effects but higher risk of heart failure exacerbation and AV block 4, 2
- Combination therapy: When combined with beta-blockers, dihydropyridines like amlodipine are safer than verapamil or diltiazem, which can cause excessive bradycardia and AV block 5
Clinical Application by Angina Type
For Stable Exertional Angina
- Start with amlodipine 5mg once daily
- Titrate to 10mg daily if needed for symptom control
- Can be combined with beta-blockers safely for enhanced efficacy 4, 1
For Vasospastic (Prinzmetal's) Angina
- Amlodipine has demonstrated significant reduction in attacks (approximately 4/week reduction) 1
- All CCBs are effective for vasospastic angina due to their coronary vasodilatory effects 6
- Beta-blockers should be avoided as they may worsen vasospasm 4
For Unstable Angina
- Calcium channel blockers provide symptom relief but should be used with other therapies
- Dihydropyridines like amlodipine should not be used without concomitant beta-blocker therapy 4
- Non-dihydropyridines (diltiazem, verapamil) can be used without beta-blockers in selected patients 6
Important Precautions and Contraindications
- Heart failure: CCBs should be avoided in patients with significantly impaired left ventricular function; amlodipine is the safest option if a CCB is necessary 4
- Conduction disorders: Verapamil and diltiazem should be avoided in patients with AV conduction abnormalities 4
- Combination therapy: When combining with beta-blockers, dihydropyridines like amlodipine are safer than non-dihydropyridines 5
- Reflex tachycardia: May occur with short-acting dihydropyridines; amlodipine's gradual onset minimizes this effect 2, 1
Dosing Recommendations for Amlodipine
- Starting dose: 5mg once daily
- Maintenance dose: 5-10mg once daily
- Elderly patients: Consider starting at 2.5mg once daily
- Administration: Can be taken with or without food 1
Amlodipine's long half-life provides consistent 24-hour coverage with once-daily dosing, making it the most practical and effective CCB for most patients with angina.