The long-term effects of botulinum toxin type A (Botox) in patients with severe movement disorders confirm the safety of the toxin's use in controlled dosages, according to a recent study at Baylor College of Medicine in Houston. The study's results are reported in today's online edition of Movement Disorders.
The study, in which Dr. Joseph Jankovic, professor of neurology and director of BCM's Parkinson's Disease Center and Movement Disorders Clinic, served as the principal investigator, analyzed the use of Botox in patients with neurological disorders involving dystonia, characterized by involuntary, repetitive muscle contractions. All 45 BCM patients who participated in the study had used Botox for at least 12 years, and some were treated for up to 19 years.
"Botulinum toxin is not only used to smooth out wrinkles but is used to treat very serious and potentially disabling disorders," said Jankovic. "There are virtually a hundred different indications for the therapeutic use of Botox."
Mild side effects, such as transient difficulty swallowing or droopy eyelids, occurred in roughly one-third of the patients over the course of about 16 years. Researchers noticed that a gradual increase in dosage over time resulted in more effective alleviation of symptoms.
When botulinum toxin, one of the most toxic substances known to mankind, is purified and injected in small amounts by a skilled clinician, it relaxes muscle tissue and prevents involuntary muscle spasms. Jankovic and other neurologists at BCM pioneered the use of Botox as a therapeutic method for dystonia patients in 1981. Approximately 3,100 patients have since received Botox at BCM's Movement Disorders Clinic.
"In addition to this report of our longitudinal follow-up we also analyzed the long-term effectiveness and safety of this treatment based on reported studies," Jankovic said.
In that systematic review of 90 clinical studies, in which patients were asked to rate the outcome of their treatment with botulinum toxin type A, patients consistently reported that the treatment significantly improved their ability to function and participate in daily activities, quality of life and their overall satisfaction with treatment. The first-ever review, which included studies across a diverse array of 24 medical conditions and cosmetic uses, was recently published in the peer-reviewed journal Clinical Neuropharmacology.
"While we have an enormous amount of data showing that botulinum toxin type A is an extremely safe and effective treatment for a variety of therapeutic and cosmetic uses, the important thing for patients is whether this translates into meaningful improvements in their daily lives," said Jankovic. "Our review makes clear that treatment with botulinum toxin type A accomplishes this across a wide range of chronic and debilitating disorders and conditions."