Oral phenazopyridine non-inferior to intravesical lidocaine for pain control in overactive bladder: Study

USA: Oral phenazopyridine is non-inferior to intravesical lidocaine for procedural pain control in women receiving intradetrusor onabotulinumtoxinA injections for idiopathic overactive bladder (OAB), finds a recent study in the American Journal of Obstetrics and Gynecology. Also, phenazopyridine was found to be well-tolerated by participants and allows for te procedure to be performed with similar ease and is tied with shorter appointment times. 

Intradetrusor onabotulinumtoxinA injections' efficiay for the manegemt of idiopathic overactive bladder is well established in previous studies. The injections are performed typically in the office setting utilizing local analgesia, most commonly a 20-30 minute intravesical instillation of lidocaine. However, there is not much data evaluating alternative bladder analgesics.

Against the above background, Lauren E Stewart, Warren Alpert Medical School of Brown University/Women & Infants Hospital of Rhode Island, RI, and colleagues aimed to compare pain scores in women undergoing intradetrusor onabotulinumtoxinA for idiopathic OAB between women randomized to pre-procedure oral phenazopyridine versus intravesical lidocaine.

The study included non-pregnant adult females with idiopathic OAB, scheduled for office injection of 100 units intradetrusor onabotulinumtoxinA. They were randomized to either 200mg of oral phenazopyridine taken 1-2 hours preprocedure versus a 20-minute preprocedure intravesical instillation of 50mL 2% lidocaine. Participants with neurogenic bladder, and those who had received intradetrusor onabotulinumtoxinA injections in the previous 12 months were excluded. 

Pain measured by a 100mm visual analog scale (VAS) was the primary outcome. Collection of demographic characteristics and overall satisfaction with the procedure was done. Question about cystoscopic visualization, ease of procedure, and perception of participant comfort were answered by the providers. Prespecified non-inferiority margin was set to equal the anticipated MCID of 14mm.

A planned sample of 100 participants, 50 in each treatment arm, provided 80% power to detect non-inferiority at a significance level of .05. A modified intention to treat analysis was performed and variables were compared by T-test or Fisher's exact test. 

111 participants were enrolled; complete data was obtained for 100 participants. 47 participants were randomized to phenazopyridine and 53 to lidocaine. 

The authors conclude, "In women receiving intradetrusor onabotulinumtoxinA injections for idiopathic OAB, oral phenazopyridine was non-inferior to intravesical lidocaine for procedural pain control."

Reference:

Stewart LE, Siddique M, Jacobs KM, Raker CA, Sung VW. Oral Phenazopyridine vs Intravesical Lidocaine for Bladder OnabotulinumtoxinA Analgesia: A Randomized Controlled Trial (OPIL). Am J Obstet Gynecol. 2022 May 14:S0002-9378(22)00370-2. doi: 10.1016/j.ajog.2022.05.025. Epub ahead of print. PMID: 35580634.