Botulinum toxin for treatment of urinary incontinence due to detrusor overactivity: a systematic review of effectiveness and adverse effects

Study design: Systematic review. Objective: To evaluate effectiveness and adverse effects of botulinum toxin (BTX) for treatment of urinary incontinence (UI) due to detrusor overactivity ( DO). Methods: Randomized controlled trials published in English before November 2006 were included if they enrolled subjects with UI caused by DO and reported incontinence outcomes. Results: Three trials totaling 104 subjects with DO refractory to antimuscarinic treatment were included. Two BTX-A trials enrolled primarily patients with NDO secondary to spinal cord injury (SCI) (93%). BTX-A decreased daily UI episodes compared to placebo but the reductions were only significantly different at a few of the time intervals during 24 weeks of follow-up. BTX-A was superior in reducing daily UI episodes in SCI subjects compared to intravesical resiniferatoxin at 12 and 18 months after injections. A small crossover study found BTX-B significantly more effective than placebo in reducing weekly UI episodes in subjects with predominately idiopathic DO. Adverse events (AEs) in BTX-A-treated subjects included urinary tract infection, pain at the injection site, hematuria and autonomic dysreflexia. Four subjects treated with BTX-B reported autonomic AEs. Conclusions: BTX may improve UI for subjects with refractory DO. The preferred dose and type of BTX is not known. Long-term efficacy and safety remain unclear and require conduct of larger RCT using standardized and validated clinical outcomes measures.