In two studies focused on the pharmacokinetics and efficacy of methadone in adolescents undergoing major spine surgeries, different dosages of methadone were explored for their analgesic effects. Initially, 31 children aged 5 to 18 years received methadone doses of 0.1, 0.2, or 0.3 mg/kg at the start of anesthesia, showing linear pharmacokinetics across these doses. While a trend towards reduced analgesic needs with higher methadone doses was noted, the difference was not statistically significant, possibly due to the small sample size. Another study involved 17 adolescents aged 12 to 19 years receiving 0.25 mg/kg of methadone before the incision, finding the average concentration of methadone fell below the established minimum effective concentration for significant analgesia within the first hour post-administration, suggesting the need for additional dosing to maintain effective analgesia levels for 24 hours.
Additionally, a randomized, double-blinded trial involving 35 children aged 3 to 7 years undergoing significant surgical interventions compared methadone and morphine administration at induction. Those in the methadone group experienced fewer instances of severe pain and required fewer analgesics in the first three postoperative days than their morphine counterparts. Another retrospective study evaluated anesthesia approaches in pediatric patients undergoing the Nuss procedure for pectus excavatum correction. This study highlighted that the group receiving multimodal anesthesia with methadone (0.1 mg/kg) benefitted from significantly lower total postoperative opioid consumption, experienced less uncontrolled pain, and had shorter hospital stays compared to groups receiving general anesthesia with standard opioids, epidural anesthesia, or multimodal anesthesia without methadone.
We can reasonably conclude that methadone, administered at induction of anesthesia, offers a promising alternative for managing postoperative pain for pediatric and adolescent patients undergoing major surgeries. Its pharmacokinetics suggest that methadone provides a more consistent analgesic effect compared to traditional short-acting opioids, potentially reducing the need for additional postoperative analgesics.
