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Botox: is it really a nontoxic toxin?

Last reviewed: September 2009

If you think of Botox as a mere wrinkle-smoother, think again. Doctors now use the toxin to treat a multitude of problems, from migraines and back pain to anal fissures and even writer's cramp.

Botox and related drugs (Myobloc, Dysport) use low doses of botulinum toxin, a powerful natural poison, to paralyze overactive muscles and inhibit sweat glands. The drugs were approved by the Food and Drug Administration (FDA) for the temporary treatment of frown lines, neck spasms, severe hand and facial sweating, crossed eyes, and twitching eyelids. But the off-label use of Botox and related botulinum toxin products has increased significantly, with more than 70 novel medical and cosmetic applications.

Unfortunately many of those uses are backed by scanty research, such as small studies and a lack of controlled trials. And worse, the proper dosage for off-label use is often determined through trial and error. In 2009 the FDA ordered a black-box warning (the most serious kind) on Botox and related products due to rare but potentially dangerous side effects reported in cases of children treated for muscle spasticity, an unapproved use, in addition to adults treated for approved and unapproved uses. Some patients required hospitalization, and there were also reports of deaths.

"We need better guidelines on how much of the drug should be given, particularly in children," says David M. Simpson, M.D., professor of neurology at Mount Sinai Medical Center in New York. "But in the minute doses that have been used worldwide for decades, the medication has shown a remarkable safety and efficacy profile." There is sufficient evidence—some favorable, some not so favorable--to discuss its use for the following off-label conditions:

Cosmetic treatments. The injections have been found to be useful for crow's foot, horizontal forehead lines, wrinkles around the nose, flaring nostrils, lip lines, jowl grooves, chin dimpling, and eyebrow elevation. But many studies included people who were more likely to benefit because they were younger or had fine wrinkles. The shots may not help if you have droopy eyelids, excess eyelid skin, deeply scarred, thick or oily skin, or wrinkles that can't be smoothed by spreading them apart with your fingers. And, paradoxically, Botox can actually cause droopy eyelids.

Headaches. Although the toxin is commonly used to treat this condition, a 2009 analysis of randomized controlled trials involving 1,600 patients found that it didn't prevent the occasional migraine. Evidence to date suggests it's probably ineffective for chronic tension headaches as well. The American Academy of Neurology (AAN) said last year that despite the popularity of botulinum toxin in headache treatment, it's ineffective for migraine headaches and unlikely to help tension headaches as well.

Writer's cramp. The injections can be considered for this muscle disorder, if occupational hand therapy is of no help. They are also helpful for "musician's cramp," in which the musician's fingers contract while playing.

Voice abnormalities. This unapproved use of Botox and related products is a first-line treatment for vocal cord palsy, or spasms that produce a strained or tremulous voice.

Back pain. While some people may find relief from their back pain with the injections, the evidence is relatively weak according to the AAN. But, at least one study suggests that the injections may relieve low back pain that's predominantly on one side.

Esophageal spasms. The injections appear to reduce such symptoms as regurgitation, difficulty swallowing, and accompanying upper chest pain. While not as effective as surgery or dilating the esophagus, they may be an alternative for people who want to avoid the more serious risks of those procedures.

Excessive sweating. Several small studies have found that the toxin reduces hand sweating and facial sweating that occurs during eating.

Drooling. Some evidence suggests that the shots may control excess salivation in people with Parkinson's disease and amyotrophic lateral sclerosis (ALS).

Hand tremors. The injections probably improve tremor severity but may also result in finger weakness. They might be considered if medication fails.

Spasticity. Good evidence supports the benefits of botulinum toxin for lower-limb spasticity associated with cerebral palsy in children and for upper-limb spasticity associated with strokes in adults. The injections especially improve the gait of children with tightened calf muscles. In adults, they were found to be safer and more effective for upper-limb spasticity than a first-line medication, according to a 2009 study published in the Journal of Neurology, Neurosurgery, and Psychiatry. The toxin is thought to be similarly effective for adult spasticity due to multiple sclerosis or brain or spinal cord injuries.

Overactive bladder (OAB). Studies have found that the injections reduce urinary incontinence, particularly in people with a spastic bladder caused by a spinal-cord injury. In a small, 2009 randomized, controlled trial from Britain, the treatment improved the quality of life in people who had OAB with no known cause.

Chronic anal fissures. The shots appear to have a better healing rate and side-effect profile than nitroglycerin ointment for persistent tears caused by spasms of the anal sphincter. Three studies found that surgery was more effective than the toxin but in several cases caused anal incontinence.

This off-label drug use report is made possible through collaboration between Consumer Reports Best Buy Drugs and the American Society of Health-System Pharmacists. This is the fourth in a series based on professional reports prepared by ASHP.

These materials were made possible by a grant from the state Attorney General Consumer and Prescriber Education Grant Program, which is funded by the multi-state settlement of consumer fraud claims regarding the marketing of the prescription drug Neurontin (gabapentin)

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