Can sucralfate (carafate) cause melena (black tarry stools)?

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Last updated: April 16, 2025View editorial policy

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From the Guidelines

Sucralfate does not typically cause black tarry stools, and if such symptoms occur, they may indicate an underlying condition requiring immediate medical attention. Black tarry stools, also known as melena, are usually a sign of upper gastrointestinal bleeding rather than a side effect of sucralfate 1. In fact, sucralfate is often prescribed to treat and prevent ulcers in the stomach and intestines by forming a protective coating over damaged tissue. The medication works by creating a barrier that protects the ulcer from stomach acid and enzymes, allowing it to heal. Common side effects of sucralfate include constipation, dry mouth, nausea, or stomach discomfort, but not black stools.

Some key points to consider:

  • Sucralfate is used for stress bleeding prophylaxis and does not decrease intragastric acidity or significantly increase gastric volume 1.
  • The use of sucralfate has been compared with other agents like antacids and H2 blockers in various studies, showing mixed results regarding the risk of ventilator-associated pneumonia (VAP) 1.
  • If you are taking sucralfate and experience black tarry stools, this could indicate bleeding in your digestive tract and requires immediate medical attention. This symptom might be related to the underlying condition for which you're taking sucralfate rather than the medication itself. Always consult with your healthcare provider about any concerning symptoms while taking medications.

It's essential to weigh the risks and benefits of each regimen when considering stress ulcer prophylaxis, especially in critically ill patients or those at risk for gastrointestinal bleeding 1. Additionally, managing hyperglycemia and avoiding unnecessary transfusions can also impact patient outcomes in related contexts 1.

From the Research

Sucralfate and Black Tarry Stools

  • There is no direct evidence in the provided studies that sucralfate causes black tarry stools 2, 3, 4, 5, 6.
  • The studies focus on the use of sucralfate in preventing or treating gastrointestinal diseases, such as gastro-esophageal reflux, gastritis, peptic ulcer, and stress ulcer, as well as its comparison with ranitidine in terms of efficacy and side effects 2, 3, 4, 5, 6.
  • None of the studies mention black tarry stools as a side effect of sucralfate or report any instances of this condition in patients treated with the drug 2, 3, 4, 5, 6.

Gastrointestinal Bleeding and Sucralfate

  • Some studies suggest that sucralfate may be effective in preventing minor upper gastrointestinal bleeding in certain patient populations, such as those requiring mechanical ventilation 3, 6.
  • However, the evidence is not consistent, and one study found that ranitidine was more effective than sucralfate in preventing clinically important gastrointestinal bleeding in critically ill patients requiring mechanical ventilation 6.

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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