Study: Methadone Reduces Postoperative Opioid Use in Pediatric Tonsillectomy

A recent double-blind, randomized, parallel group trial investigating the intraoperative use of methadone to reduce postoperative opioid consumption for children undergoing tonsillectomy found that single-dose methadone, particularly at a dose of 0.15 mg/kg, resulted in lower opioid use during the postoperative period compared to short-duration opioids like fentanyl.

With more than 500,000 pediatric tonsillectomies are performed annually in the United States, with often severe postoperative pain. Current practices generally involve the use of short-duration opioids such as fentanyl, but these have limitations due to their relatively short half-life, leading to the need for repeated dosing and increased risk of opioid-related side effects. The longer half-life of methadone (1 to 2 days) suggests that it might offer a more sustained analgesic effect, potentially reducing the need for additional opioids in the postoperative period.

In this study, the researchers compared the effects of a single intraoperative dose of intravenous methadone with as-needed fentanyl for postoperative pain management in children (ages 3 to 17) undergoing tonsillectomy. Methadone was administered in a dose escalation paradigm, starting with 0.1 mg/kg and increasing to 0.15 mg/kg based on the child's age and ideal body weight. The primary outcome of the study was the total 7-day opioid use, measured in oral morphine equivalents per kilogram. Secondary outcomes included opioid use in the postanesthesia care unit (PACU), daily pain scores, and the total number of opioid doses used during the first week following surgery.

The study placed participants (N = 60) in three groups: control, with the use of fentanyl (n = 20), methadone 0.1 mg/kg (n = 20), and methadone 0.15 mg/kg (n = 20). The results showed that total 7-day opioid use was lower in both methadone groups compared to the control group. In the control group, the median total 7-day opioid consumption was 1.5 mg/kg (interquartile range [IQR] 1.2 to 2.1), while it was reduced to 0.9 mg/kg (IQR 0.1 to 1.4) in the 0.1 mg/kg methadone group (P = .045) and 0.5 mg/kg (IQR 0 to 1.4) in the 0.15 mg/kg methadone group (P = .023). Opioid use in the PACU was also significantly lower in the methadone groups, with the 0.15 mg/kg methadone group showing no opioid use in the PACU (P = .021). Postoperative pain scores did not differ significantly between groups, suggesting that methadone did not compromise pain control despite its opioid-sparing effects. There were no serious opioid-related adverse events reported.

"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,” the study authors concluded.

Reference

Einhorn LM, Hoang J, La JO, Kharasch ED. Single-dose intraoperative methadone for pain management in pediatric tonsillectomy. Anesthesiology. 2024;141(3):463-474. doi:10.1097/ALN.0000000000005031