Examples

How It Works

Calcium channel blockers help treat coronary artery disease by:

• Increasing blood flow to the heart muscle by expanding (dilating) the coronary arteries.
• Possibly help to prevent a spasm of the coronary arteries.
• Lowering blood pressure and the workload on the heart, which allows the heart muscle to function with less oxygen and blood flow.
• Sometimes slowing a rapid heart rate and controlling irregular heart rhythms.

Why It Is Used

Calcium channel blockers are commonly used in people with coronary artery disease who have one or more of the following conditions:¹

• Stable angina
• Episodes of spasm affecting the coronary arteries
• Inability to take beta-blockers, or beta-blockers are ineffective in controlling a rapid heart rhythm

How Well It Works

Calcium channel blockers can help reduce the severity and frequency of chest pain when beta-blockers cannot be used.¹ Unlike beta-blockers, however, these medications do not reduce your risk of a future heart attack.

Side Effects

Side effects vary depending on the drug, but may include:

• Slowed heart rate or irregular heart rhythm.
• Flushing, a pounding sensation in the head, dizziness, headache.
• Leg swelling.
• Decreased blood pressure.
• Tingling sensations in the arms or legs.
• Weakness.
• Constipation.

Nifedipine, verapamil, and diltiazem may cause skin rash or breast enlargement.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Calcium channel blockers are most effective when they are combined with nitrates and beta-blockers, but their dosage must be monitored carefully to prevent side effects. Nifedipine, nicardipine, amlodipine, and felodipine are used most commonly in people already taking beta-blockers. You can also take amlodipine in a combination dose with the statin atorvastatin, which treats high cholesterol. Therefore, this combination helps reduce chest pain and treats high cholesterol at the same time.

In general, the long-acting forms (taken once a day) of calcium channel blockers are preferred over the short-acting forms (taken 2 to 4 times per day).

Verapamil, diltiazem, and nifedipine may worsen heart failure. Amlodipine, felodipine, and nisoldipine do not appear to worsen heart failure.

Verapamil or diltiazem sometimes are used when a person cannot take beta-blockers.

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