Randomized controlled trial of belladonna and opiate suppository during intravesical onabotulinum toxin A injection

Background: Intravesical injection with onabotulinum toxin A injection can be performed in-office under local anesthesia. Rectally administered pain medication presents a potentially feasible and previously uninvestigated adjunct to office-based anesthesia protocols.

Objective: The primary aim of this study was to determine whether adding a belladonna and opiate suppository to standard lidocaine instillation resulted in reduction of bladder injection pain during onabotulinum toxin A injection procedure.

Study design: This was a prospective, randomized, double-blind, placebo-controlled study of patients undergoing onabotulinum toxin A bladder injection at a single clinic. Patients age ≥18 years, who met clinical criteria for invasive treatment of refractory urinary symptoms, had previously documented postvoid residual volumes <150 mL, and elected for in-office intravesical onabotulinum toxin A injection were eligible to participate. Participants were randomized by computer-generated block randomization to receive a belladonna and opiate (belladonna alkaloid with morphine 16.2/7.5 mg) or placebo suppository. Suppositories were placed immediately prior to lidocaine-based anesthesia, which all participants received. All participants underwent a standardized injection procedure using the same rigid cystoscope, needle type, and injection pattern (20 injections total). A 0-10 numeric rating scale was used to assess pain intensity before anesthesia and suppository, 40 minutes after administration of anesthesia and suppository, after first 10 bladder injections, and immediately after completion of 20 injections. Pain increase during procedure was calculated using the difference between score 40 minutes after administration of anesthesia and suppository and score after first 10 bladder injections. Postvoid residual were measured immediately postprocedure and 2 weeks later. Patient satisfaction with pain control was measured using a Likert scale. Our primary outcome was change in pain level from anesthetic baseline to midprocedure (score after first 10 bladder injections to score 40 minutes after administration of anesthesia and suppository). A final sample size of 26 patients was needed to have 80% power (alpha = 0.05) to detect a 50% reduction in bladder injection pain during the procedure as defined by our primary outcome. An intent-to-treat approach was used for all analyses.

Results: In all, 26 participants were enrolled and randomized with 13 in each study arm. Participants in the treatment group were slightly older than in the placebo group (P = .05); there were no statistically significant differences in medical comorbidities. Median score after first 10 bladder injections to score 40 minutes after administration of anesthesia and suppository for the placebo group and treatment group was 4 (range 1-10) and 5 (range 0,9), respectively (P = .94). Median scores immediately after completion of 20 injections for the placebo group and treatment group were 3 (range 0-10) and 2 (range 0,8), respectively (P = .29). There were no significant differences in preinjection pain scores reported before anesthesia and suppository and at 40 minutes after administration of anesthesia and suppository. Postprocedure postvoid residual >200 mL was noted in 5 (38%) of the placebo group and 3 (23%) of the treatment group (P = .67). Two-week postprocedure postvoid residual >200 mL was noted in 3 (25%) of the placebo group and 2 (15%) of the treatment group (P = .64) for an overall rate of 20%. Eleven (84%) participants in each group reported being "mostly satisfied" or "very much satisfied" with pain control.

Conclusion: Belladonna and opiate suppository use did not significantly reduce bladder injection pain, or increase risk of urinary retention immediately postprocedure or 2 weeks later. Satisfaction with pain control among onabotulinum toxin A injection patients is high.