April 29th, 2003
By Kathleen Nelson, Globe Correspondent
Botox, in spite of its reputation, isn't just for removing wrinkles. For 20 years, its official use was strictly therapeutic. Its muscle-relaxing qualities were first used to treat crossed eyes and to relieve eyelid spasms. When doctors observed that wrinkles disappeared on the paralyzed side of the face of victims of stroke or Bell's palsy, they theorized that immobilizing facial muscles with Botox also might cause wrinkling to disappear. It did. To the delight of many, the FDA last year approved Botox to temporarily remove wrinkles. Now researchers are evaluating new therapeutic uses, including controlling overactive muscles and relieving chronic pain.
When botulinum toxin is ingested in tainted food, it can fatally paralyze heart and lung muscles, but the Botox injections that doctors use deliver only a tiny, purified dose of the toxin. Botox works like this: Normally nerves send a signal telling muscle fibers to contract by releasing a chemical called acetylcholine. Botox stops the release of the chemical and therefore the muscle's contraction.
Barbara Karp, a neurologist at the National Institutes of Health, has been using botulinum toxin for more than a decade to treat the excessive muscle contractions that cause spasticity in cerebral palsy, or in dystonia, a neurologic disorder that can cause limbs to contort or a hand to curl up.
''For a deadly toxin, it turns out to be a very safe medication,'' Karp said. There are few side effects and long-term symptoms, although some people experience muscle weakness or achy, flu-like symptoms after injection. A repeatedly treated muscle will atrophy, but when injections are stopped, working the muscle returns it to normal size, Karp said.
Neurological diseases may cause other symptoms that Botox can help control. Producing too much saliva can make talking and eating difficult for some patients, or cause drooling. Nerve endings in the mouth cause overproduction in the salivary glands of these patients, and, in one study, injecting the toxin into the glands reduced salivation in most participants.
An injection into the complex web of facial muscles, however, may result in droopy eyelids, difficulty swallowing or speaking, or dry mouth. The results generally wear off in three to six months.
Botox can help people who sweat excessively, too. Those who suffer hyperhidrosis literally drip sweat from their hands, feet, and armpits. Here again, Botox works by blocking the release of acetylcholine, which activates the sweat glands that work overtime in hyperhidrosis. In a study, subjects who had one armpit injected with Botox and the other with a placebo sweated much less from the toxin-treated armpit.
Botox also can stop contractions in the smooth muscle of the gastrointestinal system, and it is used from one end of the digestive tract to the other to do just that. When the lower portion of the esophagus, or food pipe, constricts, people sometimes experience chest pain and vomiting, as well as difficulty swallowing, a condition known as achalasia. Gastroenterologists use an endoscope to guide a flexible needle down patients' throats and deliver Botox, relaxing the contracting band of muscle and relieving their symptoms.
Botox injections also have helped some people with chronic bladder contractions. ''Overactive or leaky bladder is becoming more common,'' said Michael Chancellor, director of the Neurourology and Urinary Incontinence Programs at the University of Pittsburgh School of Medicine. Such patients may have urine escape when it isn't supposed to, when they cough or sneeze, for example. ''For patients with overactive bladders who have tried incontinence pills and exercise without success, an injection of Botox into the bladder can help relax the overactive bladder muscle spasms,'' Chancellor said.
Another group of patients, he said, have the opposite problem - difficulty relaxing the urinary sphincter muscle. Christina Sommers has multiple sclerosis, and used to wake up many times a night feeling like she had to urinate, but was unable to do so. The inability to empty her bladder caused urinary-tract infections. Chancellor suggested either catheterization or Botox as treatment options. She chose the toxin, which relaxed her urinary sphincter so she could urinate when she needed to. ''Within three days, my bladder was normal,'' Sommers said. ''My symptoms started to come back after nine months, but the next shot lasted over a year and a half.''
Dr. Ifeoma Okoronkwo, director of the Integrative Medicine Program at Rusk Rehabilitation Center at New York University, injects Botox into the posterior neck muscles of patients with migraines. But migraines generally don't stem from muscular causes, and she suggested that the toxin may act not only on muscular pain but on pain signals sent out by the nervous system.
If Botox affects how the nervous system generates pain, the implications ''are huge,'' Okoronkwo said. ''Its uses could be limitless.'' Insurance companies generally don't cover Botox use for nonmuscular treatment, however, since it hasn't been fully studied for such uses.
Nevertheless, Botox's use is starting to catch on in other pain syndromes, such as fibromyalgia, back pain, and for women who have pain during intercourse.
''Botox and chronic pain are fascinating and we're just scratching the
surface,'' said Dr. Jennifer Gunter of the University of Colorado Health
Sciences Center. ''It may be a good therapeutic tool, but we need large
randomized studies where it is compared to placebo treatment to discover
exactly where and how Botox works on pain.''
© Copyright 2003 Globe Newspaper Company.