Imodium for Diarrhea: Safe Dosage and Side Effects

Imodium is often the go-to treatment for diarrhea and traveler's diarrhea. Loperamide, the active ingredient in Imodium, relieves diarrhea symptoms by slowing the digestive system back down to its normal rhythm.

Imodium starts to relieve diarrhea symptoms within one hour. It is available in capsule as well as regular and quick-dissolving tablet forms. Imodium is not suitable for everyone, though, including people who are younger than 12.

This article explains how Imodium works, what dose you should take depending on your age, and the side effects that can occur. It also covers who should not use Imodium, whether it is OK to use Imodium every day, and more.

What Does Imodium Do?

Imodium is a medication that is effective in reducing the symptoms of diarrhea. Specifically, Imodium works in the following ways:

  • Reduces the speed and frequency of colon contractions
  • Reduces the secretion of fluid within the large intestine
  • Increases the absorption of fluids and electrolytes into the intestinal tract
  • Increases the transit time of stool through the colon
  • Increases muscle tone in the anal sphincter, thus reducing the chances of a soiling accident
  • May have no or only a limited effect in terms of reducing abdominal pain

When You Should Not Take Imodium

Do not take Imodium if you see any sign of rectal bleeding or blood in your stool. Also, avoid it if you are running a fever or have any other signs of a bacterial infection such as Clostridioides difficile (C. diff), salmonella, or E. coli.

With a bacterial infection, you don't want to slow down the bowel because you want to help the body eliminate the infectious agent as quickly as possible.

Use by Children

Imodium is generally seen as a safe, effective remedy for the treatment of diarrhea in children over the age of 6. However, it is always a good idea to check with your child's healthcare provider before giving them any medication, even if it is available over the counter.

Imodium would not be recommended for a child who is dehydrated, malnourished, or experiencing bloody diarrhea.

Use in Pregnancy

If you are pregnant, you should not use any medication without first getting approval from your healthcare provider.

One small study published in 2008 identified a possible link between the use of Imodium in early pregnancy and several fetal risk factors. These include hypospadias (a urethra birth defect concerning the opening of the penis), large baby size, and a higher rate of Cesarean births.

Use in Inflammatory Bowel Disease

People who have inflammatory bowel disease (IBD) should not take Imodium without permission from their healthcare provider. The use of antidiarrheal medications such as Imodium places IBD patients at risk for the development of toxic megacolon, a potentially life-threatening disorder.

Imodium Dosage

For best results, follow the dosing information on the medication packaging. A typical dose of Imodium is to take 2 milligrams (mg) twice a day.

In order to reduce the risk of the Imodium working too well and providing you with a new problem—namely, that of constipation—it is recommended that you start with a small dose, perhaps limiting yourself to 1 to 2 mg over the course of a day.

If necessary, you can increase the amount of Imodium that you take. The most you should ever take in a day is 8 mg unless your healthcare provider advises you otherwise. Be sure to drink lots of water while taking Imodium.

Imodium doesn't stop diarrhea immediately, but you may experience symptom relief within an hour of taking the medication. It will be at its highest level of effectiveness approximately 16 to 24 hours after you take it.

Is it OK to Use Immodium Every Day?

No. Imodium is intended as a short-term medication to treat diarrhea. You should not use it for more than two days in a row. If your diarrhea continues beyond that, stop taking Imodium and contact your healthcare provider.

Side Effects of Taking Immodium

Rare side effects of Imodium
Illustration by Cindy Chung, Verywell 

Imodium tends to be well-tolerated and to cause minimal side effects. This is because it works primarily within the large intestine. Very little of the medication enters the bloodstream and it does not cross the blood-brain barrier, thus there is no risk of addiction.

When side effects do occur, they tend to be only digestive in nature:

  • Abdominal pain or cramping
  • Bloating
  • Constipation
  • Nausea
  • Vomiting

In 2016, the FDA issued a warning regarding the misuse of Imodium. This involves the increased risk of serious heart problems from very high dosages and interactions with other medications. The warning was primarily triggered by people self-treating opioid withdrawal symptoms with high amounts of Imodium.

A Word From Verywell

Except for precautions taken with young children, pregnant women, and those with IBD, Imodium is considered to be a relatively safe, well-tolerated option for dealing with diarrhea.

If you find that you need to take Imodium on a more frequent basis, be sure to discuss your symptoms and your dosage with your healthcare provider.

Frequently Asked Questions

  • How do you poop after taking Imodium?

    Imodium can relieve diarrhea within one hour of taking it. Your poop should start to be firmer and your trips to the restroom should become less frequent. Some people experience constipation after taking Imodium. This side effect should subside within a few days.

  • Which is better: Pepto Bismol or Imodium?

    Pepto Bismol and Imodium can both be used to treat diarrhea, but Pepto-Bismol is a better choice if you have other symptoms as well. Pepto-Bismol also relieves upset stomach, heartburn, nausea, and indigestion.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Imodium brand website. Who can use Imodium?

  2. U.S. National Library of Medicine DailyMed. LABEL: imodium - loperamide hydrochloride capsule.

  3. Källén B, Nilsson E, Otterblad olausson P. Maternal use of loperamide in early pregnancy and delivery outcome. Acta Paediatr. 2008;97(5):541-5. doi:10.1111/j.1651-2227.2008.00718.x

  4. Shah SB, Hanauer SB. Treatment of diarrhea in patients with inflammatory bowel disease: concepts and cautions. Rev Gastroenterol Disord. 2007;7 Suppl 3:S3-10. 

  5. Imodium brand website. How Imodium products work.

  6. U.S. Food & Drug Administration. FDA drug safety communication: FDA warns about serious heart problems with high doses of the antidiarrheal medicine loperamide (Imodium), including from abuse and misuse. Published January 2018.

  7. U.S. Food and Drug Administration. FDA drug safety communication: FDA warns about serious heart problems with high doses of the antidiarrheal medicine loperamide (Imodium), including from abuse and misuse.

By Barbara Bolen, PhD
Barbara Bolen, PhD, is a licensed clinical psychologist and health coach. She has written multiple books focused on living with irritable bowel syndrome.