Fentanyl-sparing effect of acetaminophen as a mixture of fentanyl in intravenous parent-/nurse-controlled analgesia after pediatric ureteroneocystostomy.

BACKGROUND Although acetaminophen has been used widely and is well tolerated in children, its efficacy and safety have not been clarified when combined with an opioid in intravenous parent-/nurse-controlled postoperative analgesia. METHODS Sixty-three children (aged 6-24 months) who had undergone elective ureteroneocystostomies were enrolled in this prospective, randomized, double-blinded study. After the surgery, an analgesic pump was programmed to deliver fentanyl at a basal infusion rate of 0.25 microg.kg(-1).h(-1) and 0.25 microg/kg bolus after a loading dose of 0.5 microg/kg(-1). In the fentanyl-acetaminophen group, acetaminophen was coadministered as a solution mixture at a basal infusion rate of 1.5 mg.kg(-1).h(-1) and 1.5 mg/kg bolus after a loading dose of 15 mg/kg, whereas saline was administered to the fentanyl group. RESULTS Postoperative pain scores were similar between the two groups. The total dose (micrograms per kilogram per day, mean+/-SD) of fentanyl at postoperative days 1 (8.3+/-3.7 vs. 18.1+/-4.6, P=0.021) and 2 (7.0+/-2.4 vs. 16.6, P=0.042) was significantly less in the fentanyl-acetaminophen group compared with that in the fentanyl group. The incidences of vomiting (16.1 vs. 56.3%, P=0.011) and sedation (9.7 vs. 46.9%, P=0.019) were significantly lower in the fentanyl-acetaminophen group than those in the fentanyl group. CONCLUSIONS Acetaminophen has significant fentanyl-sparing effects and reduces side effects when combined with fentanyl in intravenous parent-/nurse-controlled analgesia for postoperative pediatric pain management.