Use of Methadone Versus Oxycodone to Facilitate Weaning of Parenteral Opioids in Critically Ill Adult Patients

Background: No previous literature has compared methadone with oxycodone for intravenous (IV) opioid weaning. Objective: To determine if a weaning strategy using enteral methadone or oxycodone results in faster time to IV opioid discontinuation. Methods: This was a single-center, retrospective, cohort medical record review of mechanically ventilated adults in an intensive care unit (ICU) who received a continuous IV infusion of fentanyl or hydromorphone for >= 72 hours and an enteral weaning strategy using either methadone or oxycodone from January 1, 2020, through December 31, 2021. Differences between groups were controlled for using Cox proportional hazards models. The primary outcome was time to continuous IV opioid discontinuation from the initiation of enteral opioids. Secondary outcomes included the primary endpoint stratified for COVID-19, duration of mechanical ventilation, ICU and hospital length of stay, and safety measures. Results: Ninety-three patients were included, with 36 (38.7%) patients receiving methadone and 57 (61.3%) receiving oxycodone. Patients weaned using methadone received IV opioids significantly longer before the start of weaning (P = 0.04). However, those on methadone had a significantly faster time to discontinuation of IV opioids than those on oxycodone, mean (standard deviation) 104.7 (79.4) versus 158.3 hours (171.2), P = 0.04, and, at any time, were 1.89 times as likely to be weaned from IV opioids (hazard ratio, HR 1.89, 95% confidence interval, CI 1.16-3.07, P = 0.01). Conclusion and Relevance: This was the first study showing enteral methadone was associated with a shorter duration of IV opioids without differences in secondary outcomes compared with oxycodone. Prospective research is necessary to confirm this finding.