Is Questran (cholestyramine) effective for treating irritable bowel syndrome (IBS)?

From the Guidelines

Questran (cholestyramine) is a viable treatment option for certain types of irritable bowel syndrome (IBS), particularly IBS-D (diarrhea-predominant) or cases involving bile acid malabsorption, as suggested by the most recent and highest quality study 1.

Key Points to Consider

• The typical dosage of Questran ranges from 4-8 grams taken 1-2 times daily, usually mixed with water or juice, with patients starting at a lower dose (4g once daily) and gradually increasing as needed to minimize side effects.
• Questran works by binding bile acids in the intestine, which can help reduce diarrhea in patients whose symptoms are caused by excess bile acids reaching the colon, a mechanism particularly relevant for patients who have had gallbladder removal or who have evidence of bile acid malabsorption.
• Common side effects include constipation, bloating, gas, and nausea, and Questran can also interfere with the absorption of other medications, so it should be taken at least 1 hour before or 4-6 hours after other medications.
• While not FDA-approved specifically for IBS, Questran is sometimes prescribed off-label when other treatments have failed, especially for patients with post-cholecystectomy diarrhea or those who have positive bile acid malabsorption tests, as supported by guidelines from the British Society of Gastroenterology 1 and the American Gastroenterological Association 1.

Clinical Considerations

• The Canadian Association of Gastroenterology clinical practice guideline on the management of bile acid diarrhea suggests testing for bile acid malabsorption using 75 selenium homocholic acid taurine or 7a-hydroxy-4-cholesten-3-one, and recommends cholestyramine as initial therapy for patients with bile acid diarrhea, including those with IBS-D 1.
• The choice of treatment should be individualized based on the patient's specific symptoms, medical history, and response to previous treatments, with consideration of the potential benefits and risks of Questran therapy.
• Patients should be closely monitored for side effects and adjustments made to their treatment regimen as needed to optimize their response to Questran and minimize adverse effects.

From the Research

Effectiveness of Questran for IBS

• Questran, also known as cholestyramine, is a bile acid binder that has been used to treat bile acid malabsorption, which can cause chronic diarrhea 2, 3, 4.
• Studies have shown that cholestyramine can be effective in treating patients with bile acid malabsorption, particularly those with mild to moderate symptoms 2, 4.
• However, the effectiveness of Questran for treating irritable bowel syndrome (IBS) is not well established, as IBS is a functional disorder with unknown causes 5, 6.
• Some studies suggest that bile acid malabsorption may be a underlying cause of diarrhea in a significant proportion of patients with IBS, and that cholestyramine may be effective in treating these patients 5, 6.
• A study published in 2021 found that 28.1% of patients with chronic diarrhea had bile acid diarrhea, and that a therapeutic trial of cholestyramine was a valid diagnostic strategy 6.
• Another study published in 2021 found that 52.6% of patients with chronic diarrhea of functional characteristics had a positive 75SeHCAT test, indicating bile acid malabsorption, but only 35.3% of patients responded to cholestyramine treatment 5.

Key Findings

• Bile acid malabsorption is a common cause of chronic diarrhea, and cholestyramine may be effective in treating these patients 2, 3, 4.
• The prevalence of bile acid diarrhea in patients with chronic diarrhea is estimated to be around 28.1% 6.
• A therapeutic trial of cholestyramine may be a valid diagnostic strategy for bile acid diarrhea 6.
• However, the response to cholestyramine treatment can vary, and some patients may not respond or may experience adverse events 5.