Effect of Phenazopyridine on Prolapse Surgery Voiding Trials

Several tools can be used to evaluate for ureteral patency during urogynecologic procedures. Typically, surgeons use urine dyes such as methylene blue, indigotindisulfonate sodium, or phenazopyridine, with the latter being restricted to oral administration. However in June 2014, the two U.S. manufacturers of indigotindisulfonate sodium stopped producing the medication and there is no prospect that it will be returning soon. Phenazopyridine is an over-the-counter medication (Azo-Gesic, Baridium, Urinary Pain Relief) that has been used safely for decades as a bladder analgesic and taints the urine orange. Over the past few months, increasing evidence suggests that phenazopyridine may reduce transient postoperative urinary retention. Transient urinary retention is common after urogynecologic surgery and is assessed postoperatively by performing a void trial (VT) prior to discharge. In a study designed to determine the time from administration of oral phenazopyridine to visualize dye from the ureters, Propst et al incidentally found that 38% of patients (19 of 49) failed postoperative VTs without phenazopyridine, but only 19% (9 of 47) failed with phenazopyridine, p=0.04. Most recently, a study by Duenas-Garcia et al designed to examine local anesthetics and urinary retention in subjects undergoing midurethral slings found that phenazopyridine decreased the VT failure rate from 30% to 8% (5). The investigators hypothesize that giving a dose of phenazopyridine the morning after surgery will significantly reduce the rate of postoperative urinary retention in women undergoing prolapse repair.