Examples

How It Works

Calcium channel blockers reduce the amount of narrowing (constriction) of the blood vessels. Although the cause of migraines is not well understood, it may have something to do with the blood vessels in the brain.

Why It Is Used

Calcium channel blockers are preventive medications that are used to prevent migraine headaches in some people who get them regularly.

How Well It Works

These medications may be moderately helpful in preventing migraines from occurring. The best evidence is for verapamil, which has been shown to be somewhat effective in reducing the number of migraines a person gets.¹

Side Effects

Usually, calcium channel blockers cause very few side effects, with constipation as the primary one. Other possible side effects include:

• Dizziness, headache, or redness in the face (flushing).
• Fluid buildup in the legs (peripheral edema).
• Rapid heart rate.

Side effects that are more common with diltiazem and verapamil include constipation and slow heart rate.

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

What To Think About

You may need to be watched closely by your doctor while you are taking calcium channel blockers if you have irregular heartbeats (arrhythmias) or other heart problems.

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

Citations

1. Drugs for migraine. (2004). Treatment Guidelines From the Medical Letter on Drugs and Therapeutics, 25(2): 63–66.

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