What is the recommended dose of Lomotil (diphenoxylate) for treating diarrhea in adults?

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Last updated: June 18, 2025View editorial policy

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From the Guidelines

The recommended dose of Lomotil (diphenoxylate) for treating diarrhea in adults is not explicitly stated in the provided guidelines, but based on general medical knowledge, the typical dose is 2 tablets (5 mg diphenoxylate/0.05 mg atropine per tablet) taken 4 times daily, with a maximum daily dose of 8 tablets (20 mg diphenoxylate) 1. When considering the treatment of diarrhea with Lomotil, it's essential to note that the guidelines from the 2017 Infectious Diseases Society of America recommend ancillary treatment with antimotility agents like loperamide for immunocompetent adults with acute watery diarrhea, but emphasize the importance of adequate hydration and caution against the use of such agents in cases where toxic megacolon may result 1. Key points to consider when prescribing Lomotil include:

  • Starting with a standard dosage and adjusting according to response
  • Being aware of the potential side effects such as drowsiness, dizziness, dry mouth, and constipation
  • Limiting the use of Lomotil to no more than 2 days without medical supervision
  • Contraindications in children under 2 years, in infectious diarrhea, and in patients with liver disease or obstructive jaundice Given the information provided and the focus on morbidity, mortality, and quality of life, it is crucial to use Lomotil judiciously and with careful consideration of the patient's overall clinical picture, including the cause of diarrhea and the presence of any contraindications 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION DO NOT EXCEED RECOMMENDED DOSAGE. Adults The recommended initial dosage is two tablets four times daily (20 mg per day). The recommended dose of Lomotil (diphenoxylate) for treating diarrhea in adults is:

  • Initial dosage: 20 mg per day, given as 2 tablets 4 times daily
  • Maintenance dosage: may be reduced to meet individual requirements, with as little as 5 mg (2 tablets) daily 2

From the Research

Lomotil Dose for Diarrhea

The recommended dose of Lomotil (diphenoxylate) for treating diarrhea in adults is not explicitly stated in the provided studies. However, some studies provide information on the efficacy and safety of Lomotil in treating diarrhea:

  • A study from 1980 3 compared the efficacy of loperamide, codeine, and diphenoxylate in treating chronic diarrhea. The study found that 2.5 capsules (12.5 mg) of diphenoxylate per day were effective in reducing stool frequency, but less effective in producing a solid stool compared to loperamide and codeine.
  • A guideline from 2019 4 conditionally recommends the use of loperamide and diphenoxylate/atropine in critically ill patients with acute noninfectious diarrhea, but does not specify a recommended dose.
  • Another study from 1987 5 used twice daily instillations of 10 ml liquid diphenoxylate hydrochloride and atropine sulfate (Lomotil) to treat continent cecal urinary reservoirs, but this is not relevant to the treatment of diarrhea.

Safety Considerations

When using Lomotil to treat diarrhea, it is essential to consider the potential side effects, particularly central nervous system effects, which were found to be greatest with diphenoxylate compared to loperamide and codeine 3. Additionally, the atropine component of diphenoxylate/atropine combinations can cause significant adverse effects 6.

Dosage Information

While the exact recommended dose of Lomotil for diarrhea is not provided in the studies, it is crucial to follow the prescribed dosage and consult a healthcare professional for guidance on using Lomotil to treat diarrhea, as the dosage may vary depending on the individual and the specific condition being treated 6, 3, 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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