Since the approval in mid-2002 of Botulinum Toxin Type A for the temporary improvement of facial wrinkling, botulinum toxins have received a great deal of publicity. In addition to their cosmetic uses, however, the toxins have a variety of medical applications, including some for people with MS.
There are seven botulinum toxins (labeled A to G). All are powerful neurotoxins (poisons) that block the release of acetylcholine at the junction of nerves and muscles. Acetylcholine is a chemical that, among other things, signals muscles to contract. Blocking the acetylcholine results in the temporary relaxation of targeted muscles. This action of botulinum toxins makes them potentially useful in the treatment of MS-related muscle stiffness (spasticity) and urinary symptoms caused by detrusor-sphincter dyssyndergia.
Botulinum toxin was first identified in 1897 as the cause of the type of food poisoning subsequently known as botulism. It wasn't until 1949 that botulinum toxin type A was shown to block signals at the neuromuscular junction. In 1989, the U.S. Food and Drug Administration (FDA) approved its use for the treatment of two muscle disorders of the eye (blepharospasm and strabismus). The botulinum toxin type A currently available in the United States is called Botox® (manufactured by Allergan, Inc.). Botulinum toxin type B is also being evaluated for use in spasticity and other conditions.
Although Allergan, Inc. has not applied for FDA approval of Botox® treatment of MS-related symptoms, many MS physicians now consider it an effective treatment option for certain types of problems. Botox® injections have been shown in clinical trials to relieve spasticity in individual muscles for up to three months, without any significant side effects. The toxin can be delivered by injection directly into an overactive muscle that has not responded to the first-line oral medications such as baclofen (Lioresal®) and tizanidine (Zanaflex®). While the oral medications continue to be the most effective strategy to manage generalized spasticity of the upper and lower limbs, Botox® is considered by many physicians to be an additional strategy for temporary management of severe spasticity in an isolated area.
Botox® has also demonstrated its usefulness in the management of certain types of urinary symptoms. Injected into the external urinary sphincter, Botox® helps to relieve the urinary urgency, frequency, dribbling, retention, and infections that can be caused by detrusor-sphincter dyssynergia. Treatment benefits, which typically last a minimum of three months, can relieve voiding problems and reduce a person's need for intermittent self-catheterization or an indwelling catheter. No significant complications or side effects have been reported.
If you have questions about the use of Botox® for the treatment
of spasticity or urinary symptoms, please consult your healthcare provider.
© 2003 The National Multiple Sclerosis Society