Intravesical botulinum toxin‐A injections reduce bladder pain of interstitial cystitis/bladder pain syndrome refractory to conventional treatment – A prospective, multicenter, randomized, double‐blind, placebo‐controlled clinical trial

<jats:sec><jats:title>Purpose</jats:title><jats:p>Intravesical onabotulinumtoxinA (BoNT‐A) injection is a beneficial treatment for interstitial cystitis/bladder pain syndrome (IC/BPS), yet its therapeutic efficacy remains to be validated. This study tests efficacy and safety of intravesical BoNT‐A injections for treatment of IC/BPS.</jats:p></jats:sec><jats:sec><jats:title>Materials and Methods</jats:title><jats:p>A multicenter, randomized, double‐blind, placebo<jats:styled-content>‐</jats:styled-content>controlled trial in patients with IC/BPS refractory to conventional treatment. Patients were randomized in a 2:1 ratio to hydrodistention plus suburothelial injections of BoNT‐A 100 U (Botox group) or the equivalent amount of normal saline (N/S group). The primary endpoint was a decrease in pain assessed using a visual analog scale (VAS) at week 8 after treatment. Secondary endpoints included voiding diary and urodynamic variables. The Wilcoxon sign rank and rank sum tests were used for statistical analyses.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>A total of 60 patients (8 males, 52 females, age 50.8 ± 13.9 years) including 40 in the Botox and 20 in the N/S groups were enrolled. At week 8, a significantly greater reduction of pain was observed in the Botox group compared to the N/S group (−2.6 ± 2.8 vs. −0.9 ±  2.2, <jats:italic>P</jats:italic> = 0.021). The other variables did not differ significantly between groups except for cystometric bladder capacity, which was increased significantly in the Botox group. The overall success rates were 63% (26/40) in the Botox group and 15% (3/20) in the N/S group (<jats:italic>P</jats:italic> = 0.028). Adverse events did not differ between the groups.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Intravesical injections of 100 U of BoNT‐A effectively reduced bladder pain symptoms in patients with IC/BPS. The adverse events were acceptable. <jats:italic>Neurourol. Urodynam. 35:609–614, 2016</jats:italic>. © 2015 Wiley Periodicals, Inc.</jats:p></jats:sec>