Continuous epidural butorphanol relieves pruritus associated with epidural morphine infusions in children

We examined the efficacy of epidural butorphanol to either prevent or relieve pruritus associated with epidural morphine infusion in children. Forty‐six children were randomized to receive either epidural morphine (M) or epidural M with butorphanol (B) for postoperative analgesia. They received bupivacaine and either M 50 μg·kg−1 or the same dose of M plus B 10 μg·kg−1. Following surgery, a continuous infusion of 0.1% bupivacaine with either M 20 μg·ml−1 or M 20 μg·ml−1+ B 4 μg·ml−1 was given at a rate of 0.3 ml·kg−1·h−1. Pain scores and pruritus scores were recorded every 4 h during epidural infusion. Subjects with a pruritus score=2 received diphenhydramine 0.5 mg·kg−1 i.v. and were switched to an alternate epidural infusion; subjects receiving M (group M) were switched to M+B while subjects receiving M+B (group B) were switched to hydromorphone (H) 4 μg·ml−1. There was no difference in the initial incidence of pruritus (group M 11/18; group B 13/28). No subject in group M required a second change of epidural infusion because of continued pruritus after being switched to M+B; five of 13 subjects in group B continued to experience pruritus after being switched to H and required a second change of epidural infusion or an alternate analgesic modality (P=0.038). The median pruritus score in the first 24 h after changing epidural infusions was 0 in subjects in group MΔ (changed from M to M+B) and 1 in subjects in group BΔ (changed from M+B to H; P=0.012). While the median sedation score in the first 24 h was 1 in both groups, there was a greater incidence of sedation scores of 2 in group B than group M (28%vs 12.3%; P=0.021). B 10 μg·kg−1 was not effective in preventing pruritus associated with bolus epidural administration of M 50 μg·kg−1 in children. B 1.2 μg·kg−1·h−1 was effective in relieving pruritus associated with continuous epidural infusion of M 6 μg·kg−1·h−1.