Botulinum A toxin intravesical injections in the treatment of painful bladder syndrome: a pilot study

Objective: We evaluated the efficacy and tolerability of botulinum A toxin (BTX-A) intravesical injections in patients affected by painful bladder syndrome with increased urinary frequency, refractory to conventional treatment modalities. Methods: Twelve women and two men were prospectively included in the study. Under short general anaesthesia patients were given injections of 200 U of commercially available BTX-A diluted in 20 ml 0.9% NaCl. Injections were performed submucosally in the trigone and bladder floor under cystoscopic control. Voiding chart, the Visual Analog Scale (VAS) for pain, and urodynamics were performed before treatment and 1 and 3 mo afterward. Results: Overall, 12 patients (85.7%) reported subjective improvement at 1 and 3mo follow-up. The mean VAS score was significantly reduced at 1 and 3 mo after treatment ( p < 0.05 for both); at the same time points daytime and nighttime urinary frequency significantly decreased ( p < 0.01 and p < 0.05, respectively), and bladder cystometric capacity significantly increased ( p < 0.01). Two patients reported incomplete bladder emptying. We did not detect any systemic side effects during or after treatment. Conclusions: The results of this pilot study indicate that BTX-A intravesical injections are effective in the short-term management of painful bladder syndrome. By modulating afferent C-fiber activity within the bladder walls, BTX-A significantly improves urodynamic parameters and reduces bladder pain and urinary frequency.