Examples

Among the calcium channel blockers, verapamil hydrochloride is the medication used most often to prevent cluster headaches. Nifedipine sometimes causes headache.

How It Works

Calcium channel blockers reduce the amount of narrowing (constriction) of blood vessels that can cause headaches involving blood vessels (vascular headaches) such as cluster headaches. It is not clear exactly how verapamil hydrochloride and other calcium channel blockers work to prevent cluster headaches.

Why It Is Used

Verapamil hydrochloride and other calcium channel blockers are used to prevent cluster headaches.

How Well It Works

Calcium channel blockers generally are effective in many people with cluster headaches. Verapamil hydrochloride is highly effective at preventing episodes of cluster headaches and chronic cluster headaches: about two-thirds of those taking daily doses improve by more than 50%.¹ Verapamil hydrochloride is sometimes combined with other medications, such as ergotamine or lithium, to effectively treat chronic cluster headaches.

Side Effects

Usually, calcium channel blockers cause very few side effects. These medications may cause:

• Constipation.
• Orthostatic hypotension (low blood pressure upon standing).
• Water retention, such as swollen legs.
• Fatigue.

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

What To Think About

These medications are relatively safe and have relatively few side effects.

People who have irregular heartbeats (arrhythmias) or other heart problems may need to be monitored closely when taking certain calcium channel blockers or high doses of these medications. Because they affect heart rhythm, diltiazem and verapamil hydrochloride should be used with caution in people who have problems with the electrical system that regulates a person's heart rate (a condition called heart block).

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Citations

1. Ekbom K, Hardebo JE (2002). Cluster headache: Aetiology, diagnosis, and management. Drugs, 62(1): 61–69.