Health Library Calcium Channel Blockers for Heart Attack and Unstable AnginaFrom Healthwise

Calcium channel blockers help treat chest pain and increase oxygen supply to the heart by:

• Increasing blood flow to the heart muscle by relaxing (dilating) the coronary arteries.
• Possibly helping to prevent 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.

Calcium channel blockers may be used to control symptoms and treat complications of a heart attack (such as arrhythmias). They may also be used if you cannot tolerate a beta-blocker.

Calcium channel blockers may help reduce the severity and frequency of chest pain when beta-blockers cannot be used. But unlike beta-blockers, these medicines have not been proven to reduce the risk of a heart attack, future heart problems, or death.

Side effects vary depending on the drug but may include:

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

Do not stop taking this medicine without first consulting your doctor.

Verapamil may cause a skin rash or breast enlargement.

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

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 a day).

Verapamil and diltiazem may make heart failure worse.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

Author:	Robin Parks, MS	Last Updated: May 5, 2009
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine John A. McPherson, MD, FACC, FSCAI - Cardiology
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