Does sodium bicarbonate reduce painful voiding after flexible cystoscopy? A prospective, randomized, double-blind,...

• To determine if sodium bicarbonate (Ural) reduces painful voiding after flexible cystoscopy.

• 300 patients over 18 years old undergoing elective flexible cystoscopy were enrolled in a randomized, double-blinded, placebo-controlled trial. Patients with active urinary tract infections, indwelling urinary catheters and/or requiring additional procedures such as biopsy and dilatation were excluded. • Painful voiding was quantified using a pain analogue scale from 0 to 10. Pre-existing painful voiding, previous experience with Ural and flexible cystoscopy were recorded. • Flexible cystoscopy was performed to a standard protocol. Patients were randomised after recruitment to receive Ural or placebo (glucose) powder four times a day for two days after the procedure. Trial outcome was assessed by estimating the change in pain incidence and severity from before to two days after by post-procedural questionnaire.

• Painful voiding was present in 84 of the 300 patients post flexible cystoscopy (45 of 160 patients receiving Ural; 39 of 140 receiving placebo), but overall mean pain scores were low (1.25; standard deviation 2.4; on a 0-10 scale). • Treatment with Ural compared to placebo was associated with a non-significant reduction in frequency of pain (28.9% vs 31.3%; incidence rate ratio 0.66; 95% CI 0.29-1.46; P = 0.30) and severity of pain (odds ratio 0.72; 95% CI 0.30-1.74; P = 0.47).

•In the replicable context of low post-cystoscopy pain levels, we believe Ural does not reduce painful voiding after flexible cystoscopy.