Methadone Maintenance Use

Continue the maintenance dose - Keep the baseline methadone going through the day of surgery, the perioperative stay and after discharge. Continuing a chronic full mu agonist lowers the risk of perioperative withdrawal, labile intraoperative hemodynamics and severe pain. Either give the usual once-daily morning dose, or, if the patient is amenable, split the same total daily dose three or four times across the day of surgery for steadier coverage.

Confirm the dose with the program - Methadone for opioid use disorder can only be dispensed by a federally sanctioned opioid treatment program or in an inpatient setting, so confirm the amount and timing of the last dose with the methadone provider rather than working from recall. Arrange for the maintenance dose to be given postoperatively so recovery from opioid use disorder isn't interrupted by the admission.

Baseline ECG for the QTc - Get a 12-lead ECG and a potassium and magnesium level before elective surgery. Then be deliberate about stacking QT-prolonging drugs; ondansetron is the usual one, and its risk climbs with hypokalemia, hypomagnesemia, bradycardia or underlying heart disease.

Tolerance is not analgesia - The maintenance dose covers withdrawal; it does nothing for the incision. Expect opioid tolerance and opioid-induced hyperalgesia, and titrate parenteral opioid on top of the home dose to the patient's actual pain rather than to a weight-based number. Treat the acute pain as a separate problem from the maintenance therapy.

Build the plan around non-opioids - Use an ERAS-style multimodal approach: alpha-2 agonists, gabapentinoids, and regional analgesia with continuous epidural or peripheral nerve catheters where the surgery allows. Methadone's own NMDA antagonism works in your favor — it reduces hyperalgesia, is anti-allodynic, and can lower the adjunctive opioid requirement and shorten the duration of postoperative pain.

Sedative stacking is the real danger - Additive sedation and respiratory depression with benzodiazepines, alcohol or other CNS depressants can be profound. Monitor with continuous pulse oximetry and capnography rather than intermittent checks, and be conservative with the recovery-room benzodiazepine.

CYP interactions cut both ways - Inhibitors of CYP3A4, 2B6, 2C19, 2C9 or 2D6 raise methadone concentrations and can cause fatal respiratory depression, and stopping a previously coadministered inducer does the same. Starting an inducer perioperatively swings it the other way and precipitates withdrawal.

Check a glucose - Methadone has been associated with severe hypoglycemia in some patients, which is easy to mistake for slow emergence.

Recognize withdrawal - Tachycardia, diaphoresis, nausea, vomiting and diarrhea after a missed or delayed dose. The fix is the maintenance dose, not more intraoperative fentanyl.

Don't confuse the maintenance drugs - Buprenorphine is a partial mu agonist with a ceiling on respiratory depression and is handled differently; naltrexone blocks the receptor outright and makes opioid analgesia unreliable or unpredictable. See the separate buprenorphine maintenance and opioid use disorder entries.

Methadone is a synthetic full mu-opioid agonist that is also a noncompetitive NMDA receptor antagonist. In maintenance treatment for opioid use disorder it is titrated to a daily dose that suppresses withdrawal and produces a narcotic blockade, so shorter-acting opioids no longer produce euphoria — and, for you, no longer produce their usual analgesia.

Two pharmacologic facts drive everything perioperative. The half-life is long and highly variable, 8 to 60 hours, against a narrow therapeutic index; steady-state concentrations and full analgesic effect are not reached until at least 3 to 5 days on a given dose, and equianalgesic conversion ratios to other opioids are not accurate in an individual patient. Second, methadone prolongs the QTc beyond 450 ms and has caused torsades de pointes at ordinary maintenance doses, not only at high analgesic doses.