Antidiarrheal Medications

In Some Cases, Antidiarrheal Drugs Might Be Unnecessary Or Not Recommended

Pills in bottle
If you have diarrhea, reaching for the anti-diarrheal drugs in your local pharmacy might not be the best idea. Image © Amy DeVoogd / Photodisc / Getty Images

An antidiarrheal is a drug that is used to slow down or stop loose stools (diarrhea). Antidiarrheal medications can be purchased over-the-counter, or they can be prescribed by a physician. In most cases of diarrhea, taking a medication will not treat the underlying cause, but may be used to alleviate the discomfort resulting from repeated watery bowel movements. Generally, antidiarrheals are used for acute, non-life-threatening situations, such as viral gastroenteritis.

For most adults, diarrhea happens a few times a year and goes away on its own. In these cases, anti-diarrheal medications probably aren't necessary, especially when the cause of the diarrhea isn't known. For people who have digestive diseases, such as inflammatory bowel disease (IBD), it might seem like a good idea to take something for the diarrhea, but in some cases it might not work, and it has the potential to be harmful. Check with your doctor about using a drug for diarrhea. If diarrhea goes on for more than a few days or if it causes dehydration.

About Diarrhea

Diarrhea is a common condition that can have a wide variety of causes. In many cases, diarrhea resolves on its own after a few days, and the cause may never be discovered. If diarrhea is caused by a bacterial infection, antidiarrheal medication is usually not recommended, as the body is expelling the bacteria through diarrhea, and trying to slow down or stop bowel movements will only cause the bacteria to linger in the body.

Do not take antidiarrheal agents when your diarrhea is accompanied by fever, severe illness, abdominal pain, or if you have blood or pus (mucus) in your stool. If diarrhea from an infection is a possibility, you should use antidiarrheal drugs only under the guidance of a healthcare professional.

About Antidiarrheal Drugs

Antidiarrheal drugs are usually not prescribed to treat IBD, because this doesn't treat the inflammation that's causing the diarrhea.

With ulcerative colitis in particular, antidiarrheal drugs have been linked to a rare but very serious condition known as toxic megacolon. Toxic megacolon is even less common in people who have Crohn's disease. Antidiarrheals should only be used by people who have IBD under the direction and supervision of a gastroenterologist.

People who have had j-pouch surgery may be advised to use antidiarrheal medications, especially during recovery from the final surgery (takedown surgery). Some people with j-pouches may use antidiarrheals on a long-term basis, while others might use them as needed when experiencing too many bowel movements a day.

Types of Antidiarrheal Drugs

Types of antidiarrheal medications include:

  • Imodium (loperamide). Imodium, which can be purchased over-the-counter, decreases the speed and number of intestinal contractions, thereby curbing diarrhea. Side effects of loperamide can include abdominal pain, dry mouth, drowsiness, dizziness, constipation, nausea, and vomiting. Because of potential side effects, some people may find that they aren't able to drive or do other activities that require concentration while taking loperamide. People not used to taking this medication on a regular basis should take care to see how it affects them.
  • Kaopectate, Pepto-Bismol (bismuth subsalicylate). Bismuth subsalicylate is better known for treating stomach upset, but it also works as an antidiarrheal and an anti-inflammatory, and it can hinder the spread of some strains of diarrhea-inducing bacteria. This medication slows diarrhea because it restricts the amount of water entering the bowels. Side effects of Pepto-Bismol include constipation, black stools, or a black tongue. Overdoses of Pepto-Bismol can be dangerous, so only take the prescribed amount and don't double up doses.

When To Call The Doctor About Diarrhea

If you experience diarrhea for more than a few days or have a fever, severe abdominal pain, blood or pus in your stool, or are unable to keep down solids and liquids, seek medical attention right away.


American Society of Health-System Pharmacists. "Loperamide." U.S. National Library of Medicine. 7 July 2015. 

American Society of Health-System Pharmacists. "Bismuth Subsalicylate." U.S. National Library of Medicine. 1 Feb 2011.

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