How It Works
It is not clear exactly how verapamil hydrochloride works to prevent cluster headaches.
How Well It Works
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 medicines, such as ergotamine or lithium, to effectively treat chronic cluster headaches.
Side Effects
Usually, verapamil causes very few side effects. Verapamil may cause:
- Constipation.
- Orthostatic hypotension (low blood pressure upon standing).
- Water retention, such as swollen legs.
- Fatigue.
- Changes in or problems with the way your heart beats (heart rhythm abnormalities).
See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)
What To Think About
People taking verapamil need to be watched closely and have regular tests when taking this medicine. Because verapamil can affect how the heart beats (its rhythm), this medicine should be used with caution in people who have problems with the electrical system that regulates the heart rate (a condition called heart block). Some research shows that all people taking this medicine should regularly have a test called an electrocardiogram (ECG or EKG) to make sure the heart's rhythm is still normal.2
Complete the new medication information form (PDF)
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Credits
| Author | Monica Rhodes |
| Editor | Kathleen M. Ariss, MS |
| Associate Editor | Pat Truman, MATC |
| Primary Medical Reviewer | Anne C. Poinier, MD - Internal Medicine |
| Specialist Medical Reviewer | Colin Chalk, MD, CM, FRCPC - Neurology |
| Last Updated | April 11, 2008 |
