Use of botulinum toxin for genitourinary conditions: What is the evidence?

Botulinum toxin A is licensed for the treatment of urinary incontinence due to neurogenic detrusor overactivity (NDO) and overactive bladder (OAB). Only onabotulinumtoxinA has at this moment such approval, in NDO at a dose of 200 U and in OAB at a dose of 100 U. Regulatory phase 3 trials have been carried out in both conditions. In NDO it was shown to decrease urinary incontinence, to improve urodynamic parameters and to increase quality of life in multiple sclerosis and spinal cord injured patients. Adverse events included urinary tract infections and necessity of de novo clean intermittent catheterization, which occurred mainly in patients with multiple sclerosis. In OAB patients with urge incontinence, onabotulinumtoxinA decreased urinary incontinence and micturition frequency while improving quality of life. Again, main adverse events were urinary tract infections and transient urinary retentions. Long-term studies in both NDO and OAB demonstrate the efficacy and safety of the treatment. Available phase 3 trials of onabotulinumtoxinA in benign prostatic hyperplasia did not show any relevant efficacy in improving lower urinary tract symptoms.