FDA approves Botox for migraine headaches

The Food and Drug Administration approved the drug for patients who experience 15 or more days of migraine headaches per month. Allergan, which specializes in beauty and eye-care drugs, said roughly 3.2 million people in the U.S. have chronic migraines.

For the new use, doctors are directed to inject patients in the neck or head every 12 weeks to dull future headaches.

Doctors currently use a wide variety of medications to treat migraines, ranging from over-the-counter painkillers like Advil to prescription narcotics like codeine. Many patients also respond to changes in diet or lifestyle, such as reducing caffeine or stress.

"This condition can greatly affect family, work and social life, so it is important to have a variety of effective treatment options available," said FDA's Dr. Russell Katz, director of neurology products, in a statement.

The FDA approved the new use based on two company studies of more than 1,300 patients who received either a Botox injection or a dummy injection. Patients who received Botox reported slightly fewer "headache days" than patients given the sham treatment. In the more significant of the two studies, patients on Botox reported about two fewer headache days than patients who didn't receive the drug.

Botox, which was introduced in 1989, is one of Allergan's top drugs, accounting or more than $1.3 billion of the company's $4.4 billion sales in 2009. The drug is most famous for its ability to smooth frown lines on aging foreheads, but it's also approved to treat neck spasms, eye muscle disorders and excessive underarm sweating.

The drug won approval earlier this year to treat spasms in the elbows, wrists and fingers. But it's also widely used off-label to treat broader movement disorders such as cerebral palsy. Botox works by blocking the connections between nerves and muscle, temporarily paralyzing the muscle. The drug is a purified form of botulinum, one of the most toxic substances in the world.

©2010 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.