Examples

How It Works

These calcium channel blockers help slow the heart rate by blocking the number of electrical impulses that pass through the AV node into the lower heart chambers (ventricles).

Why It Is Used

These calcium channel blockers can be used to treat:

• Irregular heart rates (arrhythmias such as atrial fibrillation).
• Chest pain (angina) caused by coronary artery disease and high blood pressure.
• People with an irregular heart rate, chest pain, or high blood pressure who cannot take beta-blocker medicines because they have asthma.

How Well It Works

Calcium channel blockers, such as diltiazem or verapamil, can help slow a rapid heart rate. Other calcium channel blockers, such as nifedipine, have little or no effect on heart rate or may actually increase the heart rate.

Side Effects

Side effects vary, depending on the individual medicine, but may include:

• Slow heart rate.
• Flushing.
• Headache or a pounding sensation in the head.
• Dizziness.
• Leg swelling.
• Decreased blood pressure and progressive heart failure.
• Tingling sensations in the arms or legs.
• Weakness.
• Constipation.

Diltiazem or verapamil may also cause a skin rash.

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

What To Think About

Diltiazem or verapamil can sometimes trigger heart failure or make it worse.

Calcium channel blockers may have greater side effects in people with liver disease.

Some calcium channel blockers may cause problems in people with a history of heart failure, or Parkinson's disease.

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