Cluster Headache Treatment Poses Cardiac Dangers

Off-label use of verapamil linked to heart rhythm abnormalities, study finds.

By Jeffrey Perkel
HealthDay Reporter
Monday, August 13, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

MONDAY, Aug. 13 (HealthDay News) -- People who use a blood pressure drug called verapamil to treat cluster headaches may be putting their hearts at risk.

That's the finding from a British study that found heart rhythm abnormalities showing up in about one in five patients who took the drug in this unapproved, "off-label" way.

"The good news is, when you stop the drug, the effect wears off," said study lead author Dr. Peter Goadsby, professor of neurology at University College London. "So, as long as doctors know about it, and patients with cluster headaches on verapamil know they need EKGs [electrocardiograms] done, it is a completely preventable problem."

The study is published in the Aug. 14 issue of Neurology.

In a review of the medical records of 217 patients given verapamil to treat their cluster headaches, a team led by Goadsby found that 128 had undergone an EKG, 108 of which were available in the medical records.

Of those 108 patients, about one in five exhibited abnormalities (mostly slowing) in the heart's conduction system -- the "natural pacemaker" that causes the organ to beat. Most of these cases weren't deemed serious, although one patient did end up having a pacemaker implanted to help correct the problem. In four cases, doctors took patients off verapamil due to their EKG findings.

One in three (34 percent) developed non-cardiac side effects such as lethargy and constipation.

"It is a very nice piece of work, because it provides commentary on a boutique [that is, niche and off-label] use of the drug," said Dr. Domenic Sica, professor of medicine and pharmacology in the Virginia Commonwealth University Health System. He was not involved in the study.

Cluster headache affects about 69 in every 100,000 people, according to the Worldwide Cluster Headache Support Group Web site. Men are six times more likely than women to be afflicted, and the typical age of onset is around 30. According to Goadsby, the disease manifests as bouts of very severe pain, one or many times per day, for months at a time, usually followed by a period of remission.