Impact of Intravenous Methadone Administered Intraoperatively on Postoperative Opioid Utilization

Abstract

Background: Studies have shown that intravenous methadone intraoperatively can reduce opioid usage postoperatively. Objective: This study’s purpose was to evaluate the effect of intravenous methadone on postoperative opioid use. Methods: A prospective, single-center observational study was conducted to evaluate patients who received intravenous methadone intraoperatively. A control group was identified by matching procedure, gender, and age in a 1:3 ratio of methadone to control. Exclusion criteria included patients less than 18 years old or on methadone maintenance therapy. The primary outcome was morphine milligram equivalents (MME) administered 24h postoperatively. Secondary outcomes included MME administered 48h and 72h postoperatively, discharge prescription MME, daily mean postoperative pain scores, and length of hospital stay. A subgroup analysis was performed comparing opioid-naïve patients. Results: A total of 240 patients were included in the analysis. At 24h, postoperative MME was increased in the methadone group (142.6 vs 84.5; P = 0.0026). Postoperative MME was also increased in the methadone group at 48h and 72h. Daily pain scores were similar between both groups at all time intervals. Discharge prescription MME was reduced in the methadone group compared with controls, but not statistically significant. A subgroup analysis of opioid-naïve patients showed a significant reduction in MME at 48h (P = 0.0240) and daily pain scores at 24h (P = 0.0366) in the methadone group. Conclusion and Relevance: Intravenous methadone intraoperatively did not show a significant reduction in postoperative opioid use and discharge prescription MMEs when comparing all patients; however, benefit was seen when examining opioid-naïve patients.