Can ketotifen (antihistamine) or rupatadine (antihistamine) cause yellow stool, also known as acholic stools or hypocholic stools?

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Last updated: March 17, 2025View editorial policy

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From the Guidelines

Ketotifen and rupatadine are not commonly associated with causing yellow stool, and any instances of yellow stool are more likely related to other factors such as diet, supplements, or underlying medical conditions. The most common side effects of these medications include drowsiness, dry mouth, headache, and occasionally gastrointestinal disturbances like nausea or stomach discomfort 1. Yellow stool is typically associated with conditions affecting bile production or flow, rapid intestinal transit, or certain dietary factors rather than antihistamine use. Some key points to consider when evaluating the potential side effects of ketotifen and rupatadine include:

  • The lack of evidence directly linking these medications to yellow stool
  • The more common side effects of these medications, such as drowsiness and gastrointestinal disturbances
  • The importance of considering other potential causes of yellow stool, such as diet or underlying medical conditions If you notice yellow stool while taking either of these medications, it's more likely related to other factors such as diet (consuming foods with yellow coloring or high fat content), supplements containing carotenoids, or underlying medical conditions affecting the liver, gallbladder, or pancreas. Should you experience persistent yellow stool, especially if accompanied by other symptoms like abdominal pain, significant changes in bowel habits, or jaundice, it would be advisable to consult with a healthcare provider to determine the cause, as it may be unrelated to your antihistamine medication 1. In terms of the management of potential side effects, it's essential to weigh the benefits and risks of these medications, considering factors such as their efficacy in treating allergic conditions and their potential impact on quality of life. For example, ketotifen has been shown to be effective in treating uraemic pruritus, with one study demonstrating marked improvement in symptoms over 8 weeks 1. However, it's crucial to prioritize the patient's overall health and well-being, taking into account any potential side effects and monitoring for signs of adverse reactions. Ultimately, the decision to use ketotifen or rupatadine should be made on a case-by-case basis, considering the individual patient's needs and medical history.

From the Research

Ketotifen and Rupatadine Effects on Stool Color

  • There are no direct research papers to assist in answering whether ketotifen or rupatadine can cause yellow stool, also known as acholic stools or hypocholic stools.
  • The provided studies focus on the therapeutic benefits of ketotifen in treating various conditions such as eosinophilic gastroenteritis 2, preventing indomethacin-induced gastropathy 3, 4, and managing allergic disorders and bronchial asthma 5.
  • One study investigated the clinical efficacy and safety of ketotifen in treating irritable bowel syndrome with diarrhea (IBS-D) and found that ketotifen alleviated gastrointestinal symptoms and improved visceral hypersensitivity in patients with IBS-D 6.
  • However, none of the studies mention the effect of ketotifen or rupatadine on stool color, specifically yellow stool or acholic stools.
  • Rupatadine is not mentioned at all in the provided studies, making it impossible to determine its potential effects on stool color based on the available evidence.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Benefit of ketotifen in patients with eosinophilic gastroenteritis.

The American journal of medicine, 1991

Research

Ketotifen in prevention of indomethacin-induced gastropathy.

Indian journal of gastroenterology : official journal of the Indian Society of Gastroenterology, 1999

Research

Ketotifen--old drug, new indication: reduction of gastric mucosal injury.

Scandinavian journal of gastroenterology, 1993

Research

Clinical efficacy and safety of ketotifen in treating irritable bowel syndrome with diarrhea.

European journal of gastroenterology & hepatology, 2020

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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