Single-Dose Intraoperative Methadone for Pain Management in Pediatric Tonsillectomy: A Randomized Double Blind Clinical Trial.

BACKGROUND: More than 500,000 elective tonsillectomies are performed in US children annually. Pain after pediatric tonsillectomy is common, often severe, and undertreated. There is no consensus on the optimal management of perioperative tonsillectomy pain. Methadone, with an elimination half-life of 1-2 days, has a longer duration of effect than short-duration opioids such as fentanyl. The primary objective of this study was to investigate the intraoperative use of methadone for pediatric tonsillectomy. It tested the hypothesis that methadone would result in less postoperative opioid use compared with short-duration opioids in children post-tonsillectomy.

METHODS: This double-bind, randomized, parallel group trial in children (3-17 years) undergoing tonsillectomy compared single-dose intravenous methadone (0.1 mg/kg then 0.15 mg/kg age-ideal body weight, in a dose escalation paradigm) versus as-needed short-duration opioid (fentanyl) controls. Opioid use, pain, and side effects were assessed in-hospital and 7 days postoperatively via electronic surveys. The primary outcome was total 7-day opioid use in oral morphine equivalents per kilogram (OME/kg). Secondary outcomes were opioid use in the Post-Anesthesia Care Unit (PACU), daily pain scores, and total number of 7-day opioid doses used.

RESULTS: Data analysis included 60 children (20/group), age 5.9±3.7 years (mean±SD; median 4, range 3-17). Total 7-day opioid use (OME/kg median [interquartile range]) was 1.5 [1.2,2.1] in controls, 0.9 [0.1,1.4] after methadone 0.1 mg/kg (P=0.045), and 0.5 [0,1.4] after methadone 0.15 mg/kg (P=0.023). PACU opioid use (OME/kg) in controls was 0.15 [0.1,0.3], 0.04 [0,0.1] after methadone 0.1 mg/kg (P=0.061) and 0.0 [0,0.1] after methadone 0.15mg/kg (P=0.021). Postoperative pain scores were not different between groups. No serious opioid-related adverse events occurred.

CONCLUSIONS: This small initial study in children undergoing tonsillectomy found that single-dose intraoperative methadone at 0.15 mg/kg age ideal body weight was opioid-sparing compared with intermittent fentanyl.