Intravenous nalbuphine 50 microg x kg(-1) is ineffective for opioid-induced pruritus in pediatrics

This investigation evaluated the efficacy of nalbuphine in treating postoperative opioid-induced pruritus (Pr) in pediatric patients. After Ethics Board approval, the dual site, tertiary care teaching centre study recruited 212 subjects, age > or = seven years, who received opioid analgesia postoperatively. A modified, self-report colour analogue scale (CAS) scored pruritus intensity (PrI). Subjects who reported PrI score > or = 5/10 were randomized to treatment with nalbuphine 50 microg x kg(-1) iv (max 5 mg) or saline placebo. A pruritus intensity difference (PrID) > or = 50% was considered a positive outcome. Of 260 subjects approached, 212 consented and 184 received opioids. Median age was 13 yr (range 7-19) and median weight was 51 kg (range 19.6-134.8 kg). Pruritus intensity > or = 5/10 occurred in 37 (20.1%) subjects. Intravenous morphine [patient-controlled analgesia (PCA)/continuous infusion] was associated with Pr in 68% of subjects over a wide dose range (9.4-63.2 mug.kg(-1).hr(-1)). Pruritus occurred in 36% of patients in the PCA group compared to continuous opioid infusion (27%) and epidural administration (27%). Pruritus intensity difference > or = 50% was achieved in 55.6% of nalbuphine and 57.9% of saline-treated subjects. This preliminary report suggests that nalbuphine 50 microg x kg(-1) iv is not effective in treating postoperative opioid-induced pruritus in pediatric patients. The modified CAS score and PrID warrant further investigation.