Newsletters

POSTED: December 7th, 2017
POSTED IN: EM Pulse - The Official Newsletter of MOCEP, November/December 2017,

Written by: Kevin Baumgartner PGY-III, Washington University in St. Louis

As emergency physicians, we’re all too familiar with the opioid epidemic. And unfortunately, we’re getting all too familiar with treating opioid overdoses: some shifts, it seems our classic A-B-Cs take a backseat to “N” for “Narcan.” Some of our overdose patients require advanced airway management, prolonged observation, or a trauma workup, but most do just fine with supportive care and naloxone.

Heroin, fentanyl, oxycodone: these are old and well-known enemies. But what about humble loperamide? Sure, it’s an opioid, but an over-the-counter anti-diarrheal medication couldn’t be dangerous, right? And isn’t its action confined to the gastrointestinal (GI) tract, anyway?

Unfortunately, recent reports from New York and elsewhere demonstrate that loperamide is much more dangerous than we thought. The cellular mechanism that keeps loperamide in the gut (and out of the central nervous system) is a glycoprotein pump. In massive overdose, the pump can be overwhelmed, and loperamide can “leak” out of the GI tract, into the systemic circulation, and across the blood-brain barrier. There, loperamide acts just like any other opioid, causing lethargy and respiratory depression. And it appears that patients with opioid use disorders, who face significant barriers to appropriate medication-assisted therapy, have learned to exploit this property in order to stave off withdrawal or obtain their next “high.”

Unlike most opioids, however, loperamide is cardiotoxic and can cause significant QRS and QTc prolongation at high dosages. Patients may present with syncope (due to transient arrhythmias), frank ventricular dysrhythmias, or full cardiac arrest. In patients with these findings (especially if they have concurrent signs of opioid intoxication), keep loperamide overdose on your differential.

Treatment consists of good supportive care and ACLS management, as well as naloxone when indicated. Although experts like Dr. Leon Gussow of The Poison Review suggest that lipid rescue therapy may be useful, as loperamide is lipid-soluble, there isn’t any good evidence to support this therapy in practice.

So the next time you see a patient with a history of opioid abuse present with syncope, QT prolongation, arrhythmia, or full arrest, remember: diarrhea is better than defibrillation!

References

Wightman et al. “Not your regular high: cardiac dysrhythmias caused by loperamide.” Clin Toxicol 2016 Jun

Vakkalanka et al. “Epidemiologic Trends in Loperamide Abuse and Misuse.” Ann Emerg Med 2016 Nov 4

Eggleston et al. “Cardiac Dysrhythmias After Loperamide Abuse — New York, 2008-2016.” MMWR 2016 Nov 18

Gussow. “Toxicology Rounds: Opioid Abusers Using Loperamide to Get High or Alleviate Withdrawal, with Fatal Consequences.” Emergency Medicine News July 2016