Botulinum toxin is one of the most poisonous substances known to man. The lethality of botulism, a few nanograms of the toxin is capable of killing a person, would seem to make it an unlikely medical cure. Yet in its purified form botulinum toxin, sold as Botox, has been used to treat neurologic diseases that cause severe and painful involuntary muscle spasms for many years.

Recently, Botox has even gained attention for treating frown lines and crows' feet, those wrinkles, caused by furrowing of the facial muscles. And it can also be used to treat people with have excessive sweating, writers' cramp and possibly even migraines.

These diseases can include spasmatic muscular disorders such as:

spasmodic dysphonia which affects the larynx muscles and results in speech that is difficult to understand spasmodic torticollis, contractions of the neck and shoulder muscles blepharospasm, uncontrollable spasm of the eyelids oromandibular dystonia, clenching of the jaw muscles and the treatment of tics and cerebral palsy

How it works

While botulism poisoning can be life-threatening, a tiny amount of purified botulinum toxin can be therapeutic in people with severe muscle spasms. Dystonias are movement disorders in which the brain signals the muscle to constantly contract causing muscle spasms. Very minute doses of the toxin is injected into the affected muscles, and once in the body, the toxin binds to nerve endings, blocking the release of the chemical acetylcholine. With the signal blocked between the nerve and muscle, the spasms cease and the muscle relaxes, allowing people to move more freely. The toxin paralyzes or weakens the injected muscle, depending on the dose, but leaves the surrounding muscles working normally.

While treating patients with eye problems such as strabismus (crossed eyes) and blephaspasm (uncontrollable spasm of the eyelids) it was noticed that wrinkling of the face decreased in the area of the muscles that were treated with Botox. This lead to the use of Botox to treat wrinkles on the face. When the muscles of the face are paralyzed they can not contract, allowing the the skin overlying the muscles to relax smoothing wrinkles and lines. Botox works better for wrinkles in the upper part of the face. There is evidence that when treating facial wrinkles with Botox, the muscles in the face that cause wrinkles are retrained. So as Botox wears off, the retrained muscles are not used to make the same facial gestures that cause wrinkles, sometimes eliminating the need for repeated Botox treatments.

A less visible, but socially important use of Botox is in the treatment of hyperhidrosis which is excessive sweating of the underarms, hands, and/or feet. Botox is injected at the site of the problem, underarms, foot or palm, and works by blocking the signal from the nerve to the sweat gland, thereby eliminating excessive moisture. Botox will not eliminate odor, the glands responsible for sweat and odor are different. The previous treatment for hyperhidrosis involved major surgery which consisted of actually cutting the nerves that caused sweating, thereby disrupting the signal to the sweat glands.

Botox results are noticeable within two to four days after the treatment. Injections usually have to be repeated, as the effects are temporary and usually last about three to four months, although sometimes they can last over a year. This is not a cure for chronic diseases, but a definite improvement over the medical and surgical treatments previously available. The cost of the treatment depends on the amount of Botox used. Most complications are related to the toxin affecting muscles other than those intended. For example, when being treated for crows feet, the toxin may diffuse into the eyelid muscle and cause a slight drooping of the eyelid, ptosis. This weakness usually resolves within a few days to a few weeks. Since BoTox has not been in use for many years, long term effects are unknown, but no lasting side effects have been reported. It is not recommended for use by pregnant or nursing women. BoTox should be used cautiously in persons with myasthenia gravis and Eaton-Lambert syndrome.