Botulinum toxin treatment for bladder dysfunction.

Botulinum toxin A is available under three different protein complexes that are not interchangeable until appropriate comparative studies are undertaken. The best studied for the treatment of urinary incontinence as a result of neurogenic detrusor overactivity and overactive bladder/idiopathic detrusor overactivity is onabotulinum toxin A. This brand is only approved for the treatment of urinary incontinence as a result of neurogenic detrusor overactivity at a dose of 200 U and idiopathic detrusor overactivity at a dose of 100 U. In patients with detrusor overactivity as a result of spinal cord injury or multiple sclerosis, 200 U of onabotulinum toxin A should be injected in 30 different sites above the trigone. It was shown to be highly effective in curing or decreasing urinary symptoms of incontinence, increasing quality of life, increasing bladder capacity and decreasing maximal detrusor pressure. This effect was independent of the concomitant use of oral anticholinergic drugs. Adverse events were mild, mainly urinary tract infections and high postvoid residual requiring clean intermittent catheterization. In patients with overactive bladder/idiopathic detrusor overactivity, 100 U of onabotulinum toxin A should be injected in 20 sites above the trigone. It markedly decreases urinary incontinence and improves quality of life. Frequency and urgency episodes are also decreased. Adverse events are mild, mainly urinary tract infections and urinary retention. The latter occurred in just 5% of the patients. Candidates for onabotulinum toxin A treatment should be warned that the effect of the toxin is transient and that repeated injections will be required to maintain the effect in the long term. There is no evidence that repeated injections will have a decreased efficacy.