High-dose dexmedetomidine increases the opioid-free interval and decreases opioid requirement after tonsillectomy in children.

PURPOSE: Dexmedetomidine, a selective α(2) adrenoreceptor agonist, has analgesic and sedative properties, minimal impact on respiratory parameters, and reportedly decreases analgesic requirements after surgery. Given its pharmacodynamic profile, dexmedetomidine might have a role for postoperative pain control in children undergoing tonsillectomy. In this study, we hypothesized that dexmedetomidine would delay and decrease opioid requirements after tonsillectomy. METHODS: In a double-blind controlled trial, participants undergoing tonsillectomy were randomized to receive one intravenous dose of fentanyl (1 µg·kg(-1) or 2 µg·kg(-1)) or dexmedetomidine (2 µg·kg(-1) or 4 µg·kg(-1)) immediately after endotracheal intubation. Primary outcomes included requirement for rescue morphine in the initial postoperative period. RESULTS: One hundred and one children were enrolled. During the postoperative period, dexmedetomidine (2 and 4 µg·kg(-1) groups combined) significantly prolonged the opioid-free interval of children who underwent tonsillectomy compared with fentanyl (1 and 2 µg·kg(-1) groups combined) (P < 0.001). Children treated with dexmedetomidine 2 µg·kg(-1) vs dexmedetomidine 4 µg·kg(-1) had similar cumulative incidence curves for time to morphine rescue, whereas there was a small difference in time to first morphine rescue administration when comparing fentanyl 1 µg·kg(-1) vs fentanyl 2 µg·kg(-1). Furthermore, length of stay in the postanesthesia care unit was significantly longer for children treated with dexmedetomidine vs children treated with fentanyl (P = 0.0016). CONCLUSIONS: High-dose dexmedetomidine decreases opioid requirements, prolongs the opioid-free interval after tonsillectomy, and prolongs length of stay in the postanesthesia care unit. It is conceivable that these early opioid-sparing effects could benefit patients at risk for respiratory complications early in the postoperative course after tonsillectomy (e.g., patients with obstructive sleep apnea). (ClinicalTrials.gov number, NCT00654511).