Data support use of botulinum toxin to treat overactive bladder

Data from a 13-week British study add to the mounting evidence of the efficacy of botulinum toxin (Botox) for the treatment of overactive bladder.

"The results show that there is a very marked therapeutic effect arising from the injections of Botox," said James Malone-Lee, MD, a professor of medicine at University College, London. "The results are so marked that the effect has come through in a crossover design, even though there was some carry-over effect into the placebo group. It would appear to be remarkably efficacious."

The randomized, double-blind, placebo-controlled, crossover design study included 20 subjects, ages 18 to 80 years, with refractor detrusor activity indicated by urodynamics. They were injected with either a saline placebo or intra-detrusor botulinum toxin B, 5,000 IU. After 6 weeks, the treatments were randomly crossed over. A 1-week run-in period was used to collect baseline data.

The primary outcome was the difference in change in the average voided volumes, which measured 16 to 122 mL, representing a significant hike in bladder capacity, according to Dr. Malone-Lee. Weekly episodes of incontinence fell by a minimum of one episode per day up to a maximum of four fewer episodes per day. Three of the 20 patients developed acute urinary retention.

While the study looked at the efficacy of botulinum toxin type B, the authors pointed out that its short duration of action (about 6 weeks) may limit its clinical usefulness. Botulinum toxin type A may be a better option because it is a longer-acting agent.

"Because [type B] is so short acting, it might be useful in detecting how patients would respond to Botox A injection," said Dr. Malone-Lee. "The data can be used to encourage people to use Botox A with more confidence."