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.

Article at a Glance:

  • Imodium, the brand name for loperamide, is an over-the-counter drug for diarrhea.
  • It is also abused by people dependent on opioids to treat opioid withdrawal symptoms.
  • High doses of loperamide can cause fatal heart rhythm problems. The FDA has issued warnings about its risks.
  • Loperamide does not show up on a routine drug test but can be detected in specialty tests.
  • It may take up to 54 hours for a dose of loperamide to leave your 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.

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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
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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

Mobile Health Management Services. “What Are the Different Drug Panels?” Accessed November 15, 2020.

Hallare, Jericho; Gerriets, Valerie. “Half Life.” StatPearls, October 6, 2020. Accessed November 15, 2020. “Imodium.” January 22, 2020. Accessed November 15, 2020.

Food & Drug Administration. “FDA limits packaging for anti-diarrhea m[…]o encourage safe use.” September 20, 2019. Accessed November 15, 2020.

NMS Labs. “Loperamide and Metabolite, Serum/Plasma.” Accessed November 15, 2020.

NMS Labs. “Loperamide and Metabolite, Blood.” Accessed November 15, 2020.

Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.