Botulinum toxin for treating overactive bladder in men: A systematic review

We sought to systematically review the literature on the use of botulinum toxin (BTX-A) injections in the bladder to treat overactive bladder (OAB) in men.

A systematic review was performed to identify clinical trials on efficacy and safety of BTX-A injections in the detrusor for treatment of OAB in men published from inception to October 2020. Quality assessment was performed using the Cochrane Collaboration's tool for assessing risk of bias and study characteristics were extracted by two reviewers independently.

After screening 75 abstracts, 12 trials were included in the qualitative synthesis, of which 6 were conducted exclusively in men (mean age: 66.7 years). Only two were randomized controlled studies and the remaining were observational studies, mostly case series. Total number of participants in each study ranged from 28 to 146. Therapeutic response to intravesical BTX-A injection was assessed differently across the studies, which used quality-of-life symptom questionnaires and voiding diary parameters. Urodynamics findings were reported separately for men before and after intravesical injection of BTX-A in two studies only. Pooling of outcome data was possible with adverse events reported after BTX-A by seven studies, which showed urinary tract infection, urinary retention, increased postvoid residual, de novo interstitial cystitis, and hematuria rates of 29.8%, 20.0%, 37.3%, 28.3%, and 12.4%, respectively.

Limited information regarding the efficacy and safety of BTX-A bladder injections for male OAB from relatively low evidence is available. Further research is needed to better understand the risk-benefit profile of BTX-A in the male population.