Loperamide Use In Infectious Diarrhea

Loperamide (Imodium) is an antidiarrheal and antimotility agent used to help manage and treat traveler’s diarrhea, irritable bowel syndrome associated with chronic diarrhea, acute nonspecific diarrhea in patients two years and older, and reduce ileostomy output. Loperamide works by increasing intestinal transit time and helps increase the potential for reabsorption of fluid and electrolytes. It essentially works like an opioid on the gut. Off-label, loperamide can be used to treat diarrhea due to chemotherapy. Loperamide use in infectious diarrhea is a little more complicated and we wanted to share what the guidelines and clinical literature suggests. 

Loperamide Use In Infectious Diarrhea – IDSA Guidelines

The 2017 IDSA guidelines for the Diagnosis and Management of Infectious Diarrhea has a strong recommendation that antimotility drugs like loperamide should be avoided in children <18 years of age for acute diarrhea (moderate quality evidence). It should also be avoided in any patient with suspected or proven cases where toxic megacolon may result in inflammatory diarrhea or diarrhea with fever (strong recommendation, low quality evidence). When it comes to diarrhea due to C. difficile, it is advised to avoid using loperamide as an adjunct agent as it may result in more severe colitis. However, some physicians may consider using it with close monitoring and no contraindications like ileus or colonic distention.

Travelers’ Diarrhea

Travelers’ diarrhea is a common occurrence and is usually acquired through the ingestion of contaminated water or food. Most cases are due to a bacterial pathogen such as E. coli. When using antibiotics for travelers’ diarrhea, loperamide can be used as an adjunct agent to help manage symptoms. There have been consistent findings from systematic reviews and meta-analyses that loperamide helps shorten the duration of symptoms. In one systematic review and meta-analysis by Riddle, et al (2008), the authors found that antibiotic therapy with adjunctive loperamide had higher odds of clinical cure over antibiotics alone and also decreased illness duration. 


It is contraindicated for use in diarrhea associated with bacterial infections, including bacterial enterocolitis caused by salmonella, shigella, and campylobacter. Additional contraindications include patients with pseudomembranous colitis associated with broad-spectrum antibiotic use, acute ulcerative colitis, and acute dysentery accompanied by bloody stools and high fever. 

As you can see, the evidence for loperamide use in infectious diarrhea is a little all over the place and depends on the clinical situation. In most cases of acute infectious diarrhea, I fall on the more cautious side (similar to IDSA) of generally not recommending its use. This is especially true in pediatric patients. In the case of Travelers’ diarrhea, there may be some benefits but the greatest focus should be getting patients antibiotic therapy first.

Are you recommending loperamide use in infectious diarrhea?


  1. Sai N, Nguyen R, and Santos C. Loperamide. StatPearls [Internet]. Last updated 23 May 2022. Available from https://www.ncbi.nlm.nih.gov/books/NBK557885/.
  2. Shane A, Mody R, Crump J, et al. 2017 Infectious Diseases Society of America Clinical Practice Guidelines for the Diagnosis and Management of Infectious Diarrhea. Clinical Infectious Diseases. 2017;65(12): 45-80. Available from https://academic.oup.com/cid/article/65/12/e45/4557073?login=false.
  3. Riddle M, Arnold S, and Tribble D. Effect of Adjunctive Loperamide in Combination with Antibiotics on Treatment Outcomes in Traveler’s Diarrhea: A Systematic Review and Meta-Analysis. Clinical Infectious Diseases. 2008;47(8): 1007-1014. Available from https://academic.oup.com/cid/article/47/8/1007/344453?login=false.
  4. Meisenheimer E, Epstein C, and Thiel D. Acute Diarrhea in Adults. Am Fam Physician. 2022:106(1): 72-80. Available from https://www.aafp.org/pubs/afp/issues/2022/0700/acute-diarrhea.html.
  5. Leung A, Leung A, Wong A, and Hon K. Travelers’ Diarrhea: A Clinical Review. Recent Pat Inflamm Allergy Drug Discov. 2019;13(1); 38-48. PMID 31084597.


  1. AJ

    Looks like you have a type-o in this post. Loperamide decreases intestinal transit time, like other opioids.

    • Eric Christianson

      Hey AJ, thanks for the comment! I had to think this one through. I think it should be increase transit time (i.e. takes a longer amount of time and the gut moves slower). But maybe I’m crazy?

      • TN

        I believe that’s correct – Loperamide increases transit time (2 minutes –> 2 hours) and, accordingly, decreases transit speed.

        Note – endocrinologists often prescribe it to counteract the sometimes-spectacular side effects of Metformin.


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Written By Eric Christianson

March 12, 2023

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