Intravesical morphine analgesia is not effective after bladder surgery in children: results of a randomied double-blind study

PURPOSE: Intravesical morphine was recently recommended to reduce postoperative pain after reimplantation surgery for vesicoureteral reflux in children. The efficacy of such treatment, so far solely evaluated by open study, needed to be confirmed. MATERIALS AND METHODS: After parental informed consent was obtained, 80 children requiring Cohen cross-trigonal reimplantation were considered for inclusion in a double-blind study. On the day of surgery patients were randomly assigned to receive either 0.04 mg./kg. morphine per hour or placebo (normal saline) at a constant intravesical infusion rate of 0.08 ml./kg. per hour. Postoperative pain was assessed every 3 hours using a pain score adapted to patient age. If the score was above a predefined limit, patients received intravenous acetaminophen and nalbuphine alternately every 3 hours. Bladder infusion was discontinued after 48 hours. RESULTS: Mean and maximum pain scores as well as the number of scores above the limit were not statistically different when comparing the morphine and placebo groups. There was no difference in the number of doses of analgesics administered. Urine output, voiding frequency and the number of painful voiding episodes were not significantly different between the 2 groups. Plasma morphine concentrations were 3.0 +/- 2.7 and 1.9 +/- 1.9 ng./ml. at 24 and 48 hours in the morphine group and undetectable in the placebo group. CONCLUSIONS: Intravesical administration of morphine is not effective for relieving postoperative pain during the first 48 hours after intravesical ureteral reimplantation. This study emphasizes the importance of controlled studies in evaluating the effectiveness of a new drug or procedure before recommending its use for all patients.