Repeated onabotulinumtoxin-a injections provide better results than single injection in treatment of painful bladder syndrome.

BACKGROUND Onabotulinumtoxin-A (BoNT-A) is effective for the treatment of interstitial cystitis/painful bladder syndrome (IC/PBS). However, long-term follow-up does not show successful outcome after a single injection. OBJECTIVES To evaluate the efficacy and safety of repeated intravesical BoNT-A injections for treatment of IC/PBS and compare the success rates among patient groups receiving different injection numbers. STUDY DESIGN Prospective interventional study. SETTING Tertiary medical center. METHODS Intravesical injection of 100 U of BoNT-A was performed in 81 patients every 6 months for up to 4 times or until patients' symptoms significantly improved. Patients who received a single injection served as active controls. Measured parameters included O'Leary-Sant symptom indexes (ICSI) and problem indexes (ICPI), visual analogue score (VAS) for pain, voiding diary variables, urodynamic parameters, maximal bladder capacity under anesthesia, glomerulation grade, and global response assessment. Multiple measurements and Kaplan-Meier analysis were used for comparison of consecutive data and success rates among groups. RESULTS Among 81 patients, 20 received single injections, 19 received 2 injections, 12 received 3 injections, and 30 received 4 injections. The mean (± standard deviation) of ICSI, ICPI, total scores, VAS, functional bladder capacity, and daytime frequency all showed significant improvement after repeated BoNT-A treatment with different injections. Significantly better success rates were noted in patients who received 4 repeated injections (P = 0.0242) and 3 injections (P = 0.050), compared to those who received a single injection. However, there was no significant difference of long-term success rates among patients who received 2, 3, and 4 injections. LIMITATIONS Lack of placebo control group is the main limitation. CONCLUSION Repeated intravesical BoNT-A injections were safe and effective for pain relief and they increased bladder capacity and provided a better long-term success rate than a single injection did for treatment of IC/PBS.