Be Alert to Loperamide Abuse
and Misuse

Taking Very High Doses Of Loperamide Can Lead
To Serious Cardiac Events And Death.



Millions of consumers use loperamide, a prescription and over-the-counter (OTC) medication approved by the U.S. Food and Drug Administration (FDA) to relieve the symptoms of diarrhea.
Loperamide is sold in generic versions, as well as under the brand name Imodium A-D®. This drug is safe and effective when used as directed.

However safe, recent reports show a small but growing number of individuals are consuming very high doses of loperamide in an attempt to self-manage opioid withdrawal or to achieve a euphoric high. At extreme doses, these individuals may experience severe or fatal cardiac events.


Loperamide has a maximum approved daily dose of 8 mg for OTC use, and 16 mg for prescription use.

Loperamide is a peripherally acting μ -opioid agonist — a type of synthetic opiate that blocks the opioid receptors in the gut, but at very high doses can pass the blood-brain barrier and cause opioid-like effects. It has a half-life of 10.8 hours with a range of 9.1 – 14.4 hours. Nonclinical in vitro and in vivo (rabbit, guinea pig) cardiac electrophysiological safety assessments of loperamide support a large safety margin at the labelled dose, but at excessive doses, suggests that loperamide can inhibit the potassium channels (hERG) and cardiac sodium channels which could result in QT and QRS prolongation and induce arrhythmia.1 In humans, the dose and blood level that results in serious cardiac events is unknown. Data from the National Poison Data System suggests that cardiac effects are typically associated with doses of over 100 mg, but cases have been reported with lower doses as well.


Patient Profile

The low number of reported loperamide abuse cases and limited data make it difficult to determine an exact patient profile, but the data available revealed the following:

  • Patients most at risk for abusing loperamide likely have a history of substance abuse and opioid use disorder.2, 3
  • Men in their late twenties and thirties are more likely than other demographics to be diagnosed with loperamide abuse.4
  • Loperamide misuse does not seem to be limited to a certain gender or age group.

Consumers are most likely to learn about using loperamide to get high or to ease opioid withdrawal symptoms through conversations with others at rehab facilities or online. According to a 2017 report, “a spike in the number of cases of loperamide toxicity reported in 2014 and 2015 coincided with an abundance of online instructions on how to abuse [loperamide].”5


Signs of Loperamide Misuse

Signs of loperamide cardiotoxicity include:

  • Syncope or fainting
  • Rapid or irregular heartbeat
  • Unresponsiveness
  • QT interval prolongation
  • Torsades de Pointes
  • Ventricular arrhythmias
  • Cardiac arrest

Gastrointestinal complications, including nausea, vomiting, constripation, and paralyzed intestine could also be a sign of loperamide overdose.

If you encounter a patient with these signs, or other signs of addiction, consider loperamide abuse as a potential cause.