A pilot study of botulinum toxin for interstitial cystitis/painful bladder syndrome

Preliminary studies using botulinum toxin (BTX) have demonstrated some benefits in treating interstitial cystitis (IC)/painful bladder syndrome (PBS) pain. The purpose of this study was to investigate the efficacy of a periurethral injection of BTX to block urethral visceral and somatic afferent fibers, for the treatment of IC/PBS.

Twenty adult women with IC/PBS were identified from the Female Urology Clinic at our hospital. Symptom evaluation was performed using a female modification of the Chronic Prostatitis Symptom Index (CPSI), AUA Symptom Index, Graded Chronic Pain Scale, Perceived Stress Scale, and symptom improvement Visual Analog Scale (VAS). All patients were randomized to receive either botulinum toxin A (BTX-A) or placebo (normal saline). Patients randomized to BTX-A received 50 U diluted in 2 cm(3) normal saline injected periurethrally. The physician and patient were blinded to the treatment.

BTX was administered to nine women. There were no complications or side effects reported. There was no improvement between placebo and BTX-A groups in the CPSI score at 3-month follow-up (P=0.97). Additionally, there were no improvements in the other symptom indices. At follow-up, the mean VAS for the BTX group was -0.3, indicating the subjects' symptoms were the same as at the start of the study.

Periurethral injection of botulinum toxin in women did not effectively treat the pain of IC/PBS. While the results from this study are negative, there is still a valid rationale for further investigations of novel injection protocols given the dearth of current effective treatments.