The effect of botulinum-A toxin on patients with severe urge urinary incontinence

We determined the effect of 150 units of botulinum-A toxin (Botox, Allergan, Irvine, California) on subjects with severe urge urinary incontinence (UUI).

This was an open label uncontrolled clinical trial. Subjects were recruited from the female urology and urogynecology clinics at Duke University. Inclusion criteria included evidence of UUI on 3-day bladder diary, a 24-hour pad weight of 100 gm or greater, absent or minimal stress leakage, absent detrusor dysfunction, and a history of failed anticholinergic and physical therapies. Exclusion criteria included evidence of a urinary tract infection, or other correctable or neurological etiology for UUI. The detrusor of each subject was injected with 150 units of botulinum-A toxin. Evaluations were performed at 2 weeks, 6 weeks, 3 months and 6 months after injection. Outcome measures included daily incontinence episodes, Urogenital Distress Inventory and the Incontinence Impact Questionnaire, 24-hour pad weights, daily pad usage and urinalysis at all visits. Urodynamic studies were performed at the 6-week and 3-month visits.

Three subjects had uncomplicated urinary tract infections during followup. No other adverse effects occurred. Statistically and clinically significant decreases greater than 50% were seen in virtually all outcome measures at all visits up to 3 months. Most subjects showed signs of recurrent UUI by 6 months. All subjects reported remarkable subjective improvement in incontinence. No significant changes in maximal cystometric capacity, maximal detrusor pressure, peak flow or post-void residual volumes were seen.

Botulinum-A toxin can significantly decrease urge urinary incontinence and improve quality of life for 3 months after injection. Additional studies are needed to determine ideal doses, dosing intervals, safety and cost-effectiveness of this therapy.