Botulinum toxin in urinary incontinence

In recent years, botulinum toxin has been investigated for treatment of lower urinary tract dysfunction. This review discusses recently published literature related to the role of botulinum toxin in treating incontinence, including the place for repeated treatment, the differing types of toxin available and the side effects of its use.

Botulinum toxin is safe and effective in improving both urodynamic and subjective parameters. The A serotype has a longer duration of action than the B serotype and has fewer systemic side effects; hence, it is more likely to gain favour as a suitable treatment, both in patients with neurogenic detrusor overactivity and those with idiopathic detrusor overactivity. It is especially effective in reducing incontinence associated with detrusor overactivity, and repeated treatments appear safe and efficacious. A better understanding of urothelial physiology suggests that botulinum toxin not only has efferent effects but also acts on afferent pathways. The existing data as they stand at present would also suggest it to be safe in patients of all age groups.

Botulinum toxin is awaiting approval for use in lower urinary tract dysfunction. Studies have been carried out in varying populations, but few have used reduction in incontinence episodes as a primary end point. The short-term and long-term efficacy and safety of botulinum toxin as a treatment modality for those with lower urinary tract dysfunction, especially for those with detrusor overactivity refractory to anticholinergics, is, however, evidenced increasingly. Further investigation is needed, specifically large randomized placebo-controlled trials, to determine the ideal conditions for the use of botulinum toxin. Some such trials are underway and we look forward to their findings with interest.