How Long Does Imodium (Loperamide) Stay In Your System?

Imodium, sometimes abused by people trying to avoid opioid withdrawal, can stay in your system for hours, although it is rarely found on drug tests.

Imodium, the brand name for loperamide, is an over-the-counter diarrhea treatment. Although it works on opioid receptors, it does so only in the intestines and does not cross into the brain. Because the drug does not show up on routine drug screenings, it is difficult to say how long it is detectable in your system. However, based on known information about the drug’s chemistry, we can predict how long it may stay in the body.

Half-Life Of Imodium (Loperamide)

The half-life of a drug is the time it takes for your body to remove half of it from your system. The average half-life of loperamide is around 10.8 hours, although it can range from 9.1 to 14.4 hours. Since it generally takes five half-lives for a drug to be completely cleared from your system, a dose of loperamide should stay in your body for about 54 hours.

Factors That Influence How Long Imodium (Loperamide) Stays In Your System

Different factors can play a role in how long a drug like Imodium stays in your system. These include:

• Dosage form: The liquid form peaks sooner in the body than the capsule form of the drug. Blood levels of loperamide are highest around five hours after someone takes it in capsule form and around 2.5 hours after taking the liquid form. In turn, the liquid form may wear off faster.
• Dose: Since some people misuse Imodium by taking high doses, the drug may stay in their system longer than if they took a lower dose. If someone regularly misuses Imodium, it may also build up in their system, especially if they’ve been taking it for a long time.
• Age: Children have a more variable response to loperamide than adults and may process the drug differently from adults.

Imodium (Loperamide) Regulations & Drug Testing

Loperamide is available over-the-counter and does not require a prescription. Although loperamide products are not classified as controlled substances in the U.S., the FDA has begun to warn the public and medical professionals about the risks associated with loperamide abuse.

Specifically, the FDA has warned about the risk of heart rhythm problems like QT prolongation, which can lead to a fatal heart condition called Torsades de Pointes.

Due to the risk of these serious heart problems from loperamide abuse, the FDA now requires each loperamide tablet and capsule to be individually packaged. Further, packages may not contain more than 48 mg of loperamide in total.

Although loperamide does not show up on routine drug tests, specialty blood and plasma drug tests can detect it and its breakdown product desmethyl loperamide. However, it is unclear how common these tests are or how long they are sensitive to the loperamide in your body.

Editor – Melissa Carmona

Melissa Carmona puts years of writing and editing experience to work helping people understand substance abuse, addiction and mental health disorders. Read more

Medically Reviewed By – Dr. Jessica Pyhtila, PharmD

Dr. Jessica Pyhtila is a Clinical Pharmacy Specialist based in Baltimore, Maryland with practice sites in inpatient palliative care and outpatient primary care at the Department of Veteran Affairs. Read more