The efficacy of using intravesical botulinum toxin to treat overactive bladder syndrome is supported by little more than anecdotal evidence and case reports, according a Cochrane review. In addition, the optimal dose of botulinum toxin for efficacy and safety has not been identified.
Eight studies were included in the review. Overall, botulinum toxin performed better than placebos in outcomes such as incontinence episodes, bladder capacity, maximum detrusor pressure and quality of life.
Low doses of botulinum toxin (100U to150U) appeared to have beneficial effects but higher doses (300U) may have been more effective.
The treatment appeared to involve few side-effects or complications but the authors did not identify any long-term follow-up studies.
Duthie, J. et al (2007) Botulinum toxin injections for adults with overactive bladder syndrome. Cochrane Database of Systematic Reviews; issue 3: art no, CD005493. DOI: 10.1002/14651858.CD005493.pub2.