Loperamide is an antidiarrheal active ingredient available in over-the-counter (OTC) medicines that treat the symptoms of diarrhea, including traveler’s diarrhea. It may be written as loperamide or loperamide hydrochloride (HCl), but it is the same ingredient. Loperamide can be the only active ingredient in an anti-diarrheal medicine or it can be found in medicines that also treat symptoms such as gas. Loperamide is also available as a prescription product with a maximum approved dose of 16 mg per day.

Loperamide is approved by the U.S. Food and Drug Administration (FDA) and is safe and effective when used according to the Drug Facts label. Taking higher than recommended doses of loperamide can cause severe heart rhythm problems or death. Certain medications can also increase blood levels of loperamide and cause serious heart problems.

Seek immediate medical attention if you or someone taking loperamide experiences any of the following: fainting, rapid heartbeat or irregular heart rhythm, or unresponsiveness (meaning that you can’t wake the person up or the person doesn’t answer or react normally). If you develop abdominal swelling or bulging, or if your diarrhea lasts for more than two days while taking an OTC medicine containing loperamide, contact your healthcare provider. These may be signs of a more serious condition. 

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  • You are taking an antibiotic, antifungal, histamine 2 receptor antagonist, HIV medication or gemfibrozil (a cholesterol lowering drug).
  • You have a fever.
  • You have mucus in the stool.
  • You have a history of liver disease.
  • You are pregnant or breastfeeding.
  • You have ever had a rash or other allergic reaction to loperamide.
  • You have bloody or black stool.
  • Talk to a healthcare professional prior to use in children under the age of 6.
  • Your symptoms get worse.
  • Your diarrhea lasts for more than two days.
  • Seek immediate medical attention if you experience any of the following: fainting; rapid heartbeat or irregular heart rhythm.
  • You get abdominal swelling or bulging.
  • You take too much. Immediately contact a healthcare provider or the poison control national helpline at 800.222.1222.
  • Always read the OTC Drug Facts label prior to using loperamide and do not use more than recommended.
  • Talk to a healthcare provider before giving an OTC containing loperamide to a child under the age of 6.
  • Click here for more information on giving OTCs to children.

Please read the Drug Facts label carefully for active ingredient information for specific products, as some may have more than one active ingredient. If you have questions about any of the medicines you are taking or if you have any unexpected side effects, talk to a healthcare provider. And of course, keep all medicines out of the reach and sight of children.