July 15, 2013
Content provided by the Faculty of the Harvard Medical School
Excerpted from a Harvard Special Health Report
Botulism is a rare but serious paralytic illness caused by a nerve toxin produced by the bacterium Clostridium botulinum. People usually contract botulism after eating food contaminated with the toxin, which binds to nerve endings, essentially paralyzing motor nerves.
Yet the toxin is better known as a wrinkle-buster, since injecting tiny amounts above the eyes and over the bridge of the nose relaxes small areas of muscles, smoothing crow’s feet and frown lines. But onabotulinumtoxinA Injection (Botulinum Toxin Type A, Botox) has more than just cosmetic applications — it’s also approved for the treatment of cross-eye, abnormal squinting and eyelid twitching, neck and shoulder muscle spasms, and severe sweating.
In the mid-1990s, a number of anecdotal reports suggested people who got Botox injections to fight wrinkles also had fewer migraine headaches, spurring a flurry of clinical trials to test that idea. But the results have been disappointing. A review of 11 clinical trials concluded that Botox was “probably ineffective” as a treatment for episodic migraine and chronic tension headache.
However, Botox may benefit people with chronic migraine, a form of chronic daily headache in which people have headaches at least 15 days per month, at least eight of which are migraine. About 2% of adults are plagued by this crippling condition, which leaves many unable to hold down a job, do housework, or have any semblance of a normal social life.
In a two-part clinical trial, nearly 1,400 people received up to five courses of Botox into specific head, neck, and shoulder muscles every 12 weeks. After 24 weeks, people treated with Botox had fewer days with a migraine than those who received placebo injections. During the second phase, all participants received Botox for an additional 32 weeks. At the end of the study, nearly 70% of patients treated with Botox had at least half as many days with migraine. The most common side effects (neck pain and muscle weakness) were mild and short-lived, according to the study, which was published in the journal Headache in 2010 — the same year Botox was approved to treat chronic migraine in the United States.
If you are a potential candidate for this therapy, be sure to find a physician with experience doing the injections. According to headache experts, doctors require extensive training to properly administer the required 31 injections in seven different locations on the head and neck.
Last Annual Review Date: Jan 1, 2011 Copyright: Copyright Harvard Health Publications