Loperamide (also sold under the brand name Imodium®) is a prescription and over-the-counter medication approved by the U.S. Food and Drug Administration (FDA) to relieve the symptoms of diarrhea. Loperamide is safe and effective when used as directed. A small number of individuals are intentionally misusing loperamide by consuming very high doses in an attempt to self-manage their opioid withdrawal symptoms or to achieve a euphoric high. At doses higher than directed, loperamide may cause these individuals to experience severe or fatal cardiac events.

It is important to recognize this issue and address it appropriately with patients who may be misusing or who may be at risk for misusing loperamide.

Who Is at Risk for Misusing Loperamide?

There is significant evidence that loperamide misuse is linked to substance use disorder and that some people experiencing opioid withdrawal turn to loperamide to ease their withdrawal symptoms. Some people who misuse loperamide may mix it with other drugs to increase absorption and penetration across the blood-brain barrier. The available data shows that the people most at risk for misusing loperamide likely have a history of substance misuse, including misuse of opioids.

People 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.

What Are the Signs of Loperamide Misuse?

Loperamide is a peripherally acting mu opioid agonist — a type of synthetic opiate that blocks the opioid receptors in the gut. At very high doses, loperamide can cross the blood-brain barrier and may cause these individuals to experience severe or fatal cardiac events. 

It's important to recognize the signs of loperamide misuse and cardiotoxicity. Signs include syncope (fainting), rapid or irregular heartbeat, unresponsiveness, and cardiac arrest. Gastrointestinal complications including nausea, vomiting, constipation, and paralyzed intestine could also be signs of loperamide misuse.  

If you encounter a patient with these signs, consider loperamide misuse as a potential cause.

How to Screen a Patient for Loperamide Misuse

There is currently no screening tool specifically for loperamide misuse; however, there are screening tools for substance use disorder. Ask patients the right questions to identify and prevent loperamide misuse. Consider your words carefully when discussing loperamide misuse with your patients. Be cautious in your approach to avoid inadvertently letting a patient know that loperamide can be used to manage opioid withdrawal symptoms or to get high.

If you suspect a patient is misusing loperamide, ask:

• Have you been taking loperamide?

• How much loperamide do you take, and how often?

• Are you aware of the severe heart risks associated with overuse and misuse of loperamide?

If a patient reports using more than the directed dose of loperamide, educate them about the risks.

Addressing Loperamide Misuse

Over the last several years, FDA and loperamide manufacturers have been partnering together on labeling and packaging changes to help prevent loperamide misuse while preserving access to a safe and effective over-the-counter remedy for diarrhea.

If you encounter a case of loperamide misuse, contact Poison Control immediately at 800-222-1222.