ED physicians need to be comfortable with the various modalities of opioid substitution therapy (OST) and their associated complications.  We are all familiar with the patient who has missed a daily dose of methadone on the way to booking and is subsequently brought to the ED by corrections officers to address this issue.  A recent commentary in NEJM contextualizes this issue very gracefully: https://www.nejm.org/doi/full/10.1056/NEJMp1900069?query=featured_home

Let’s go over some basics.

Methadone is a full mu opioid agonist.  A 2009 Cochrane review showed that methadone is an effective maintenance therapy intervention for the treatment of heroin dependence as it retains patients in treatment and decreases heroin use better than treatments that do not utilise opioid replacement therapy.  Methadone as greater mortality than suboxone in the overdose setting.  Overdose mortality for methadone is secondary to respiratory depression and, to a lesser extent, Torsades.  It is currently the only OST supported by the evidence for use in pregnancy, is rapidly metabolized in the third trimester, which can lead to early withdrawal.

Suboxone is a combination of buprenorphine (a partial agonist) and naloxone (opioid receptor antagonist).  It is safer than methadone from an overdose standpoint.  A 2014 Cochrane review demonstrated that suboxone is superior to placebo for retention of treatment, like methadone.  Prescribing buprenorphine requires special training and a waiver from the Controlled Substances Act in the United States which residents and attendings can apply for.

When managing withdrawal in the ED, OST is safer and better for the patient and society than classic opiates/opioids.  When possible, a methadone dose should be confirmed by discussing with the pharmacy/pain clinic and a one-time, observed dose can be administered in the ED.

July 2024