Does sodium bicarbonate reduce painful voiding after flexible cystoscopy? A prospective, randomized, double‐blind, controlled trial

Study Type – Therapy (RCT) Level of Evidence 1b What’s known on the subject? and What does the study add? Post‐cystoscopy dysuria occurs in 30–54% of patients but the exact mechanism of cause is unknown. The evidence for using sodium bicarbonate to alkalinize urine and alleviate post‐cystoscopy dysuria is at best circumstantial, taken from work with women with cystitis‐type symptoms. In a double‐blinded randomized design, this study documents a post‐cystoscopy dysuria rate of 28% with a mean pain score at 48 hours of 1.3 (scale 1–10). The effect of sodium bicarbonate compared to placebo did not show a significant reduction in incidence or level of post‐cystoscopy dysuria. Objective • To determine if sodium bicarbonate (Ural®) reduces painful voiding after flexible cystoscopy. Patients and Methods • 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. Results • 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). Conclusion • In the replicable context of low post‐cystoscopy pain levels, we believe Ural® does not reduce painful voiding after flexible cystoscopy.