Intraoperative methadone: Proceed with care.

A recent review suggests minimal respiratory depression (RD) after perioperative methadone, while another identified RD in up to 37 percent of patients. A meta-analysis is equivocal. At our institution, five of 75 opioid naive patients (6.6 percent) given perioperative methadone received naloxone. We report three of these cases in detail. Two others were discovered during an electronic medical record search for opioid naïve patients who received methadone plus naloxone during their anesthesia care. Our five patients indicate that RD owing to methadone can occur with excessive perioperative adjuvant medications and/or in patients who are taking home central nervous system depressants. We define perioperative adjuvant medications as medications given by the anesthesiologist prior to induction and intraoperatively. The risks and benefits of perioperative methadone administration, specifically in patients who received post-operative naloxone, deserve further investigation.