Botulinum Toxin Injections for Adults with Urgency Urinary Incontinence or Overactive Bladder Syndrome

Intravesical botulinum toxin appears to be effective for urgency urinary incontinence or for overactive bladder symptoms, and may be as effective as sacral neuromodulation. However, the effect of botulinum toxin lasts only 6 months. Level of evidence: "B"

Intravesical botulinum toxin is suggested as second-line treatment for women with severe or neurogenic urge urinary incontinence, and other treatments are insufficient.

The recommendation is weak because of short duration of effect and cost of treatment.

A Cochrane review [Abstract] 1 included 19 studies. Participants had either neurogenic or idiopathic overactive bladder with or without stress incontinence. Comparison interventions included no intervention, placebo, lifestyle modification, bladder retraining, pharmacological treatments, surgery, bladder instillation techniques, neuromodulation and different types, doses, and injection techniques of botulinum toxin. Lower doses of botulinum toxin (100 to 150 U) appeared to have beneficial effects, but larger doses (300 U) may have been more effective and longer lasting, but with more side effects. All studies followed participants after a single intravesical injection of BTX, except in one study the participants were reinjected every six months. The length of predetermined follow up varied from six weeks in to 24 months in.

For the most part, studies reported superiority of botulinum toxin A to placebo in such outcomes as incontinence episodes, bladder capacity, maximum detrusor pressure, and quality of life. Low doses of botulinum toxin (100 U to150 U) appeared to have beneficial effects, but higher doses (300 U) may have been more effective. As the great majority of participants in the studies reviewed had neurogenic overactive bladder, the results may not be generalisable to patients with idiopathic overactive bladder.

A multicenter, open-label, randomized trial 2 comparing sacral neuromodulation (SNM) and onabotulinumtoxinA (BTX) included 298 women with urgency urinary incontinence (UUI). No difference in decreased mean UUI episodes was found over 24 mo (-3.88 vs -3.50 episodes/d, 95% CI -0.14 to 0.89; p=0.15), with no differences in UUI resolution, ≥75% or ≥50% UUI episodes reduction. BTX group maintained higher satisfaction. Other secondary measures did not differ. Recurrent urinary tract infections were higher after BTX (24% vs 10%; p<0.01),

Comment: The quality of evidence is downgraded by imprecise results (limited study size for each comparison).

References

• Duthie J, Wilson DI, Herbison GP, Wilson D. Botulinum toxin injections for adults with overactive bladder syndrome. Cochrane Database Syst Rev 2007 Jul 18;(3):CD005493 (Last assessed as up-to-date: 23 February 2010). [PubMed]
• Amundsen CL, Komesu YM, Chermansky C et al. Two-Year Outcomes of Sacral Neuromodulation Versus OnabotulinumtoxinA for Refractory Urgency Urinary Incontinence: A Randomized Trial. Eur Urol 2018;74(1):66-73. [PubMed]