Is cholestyramine effective for treating diarrhea?

From the Guidelines

Cholestyramine is effective for treating bile acid diarrhea, and it is suggested as the initial therapy for induction of clinical response in patients with this condition. The medication works by binding to bile acids in the intestine, preventing them from irritating the colon and causing diarrhea. According to the Canadian Association of Gastroenterology clinical practice guideline on the management of bile acid diarrhea 1, cholestyramine is recommended as the first-line treatment for patients with bile acid diarrhea. The typical dosage ranges from 4-16 grams daily, divided into 2-4 doses, usually mixed with water or juice and taken with meals.

Key Points to Consider

• Cholestyramine is especially useful for patients who have had gallbladder removal, ileal resection, or those with functional diarrhea where bile acids are implicated.
• Side effects may include constipation, bloating, gas, and nausea.
• The medication can also interfere with absorption of other medications and fat-soluble vitamins, so it should be taken at least 1 hour before or 4-6 hours after other medications.
• Patients should start with a low dose and gradually increase to minimize side effects.
• A systematic review of 23 cohort studies found that first-line cholestyramine was successful in 69.8% of patients overall 1.
• The Canadian Association of Gastroenterology clinical practice guideline on the management of bile acid diarrhea suggests using cholestyramine over other bile acid sequestrants as initial therapy for induction of clinical response in patients with bile acid diarrhea 1.

Important Considerations

• Cholestyramine is not effective for all types of diarrhea and works best when the cause is specifically related to excess bile acids in the colon.
• The medication should be used with caution in patients with a history of constipation or bowel obstruction.
• Patients should be monitored for signs of bile acid malabsorption, such as steatorrhea or fat-soluble vitamin deficiencies.
• The guideline recommends a trial of cholestyramine, initially, for patients with positive results from tests for bile acid diarrhea 1.

From the FDA Drug Label

ADVERSE REACTIONS ... diarrhea The FDA drug label does not answer the question.

From the Research

Effectiveness of Cholestyramine for Diarrhea

• Cholestyramine is effective in treating diarrhea caused by bile acid malabsorption, as it binds to bile acids in the gut and prevents them from stimulating electrolyte and water secretion 2.
• Patients with mild to moderate bile acid malabsorption typically respond well to treatment with cholestyramine, with abolishment of diarrhea 2.
• However, cholestyramine may not be effective in patients with more severe bile acid malabsorption, and may even worsen steatorrhea in these cases 2.

Clinical Response to Cholestyramine

• Studies have shown that patients with chronic diarrhea and a high suspicion of bile acid malabsorption may respond to cholestyramine treatment, with improved symptoms and reduced frequency of bowel movements 3, 4.
• The SeHCAT test can accurately identify patients with bile acid malabsorption who are likely to benefit from long-term cholestyramine treatment 3.
• However, response to cholestyramine can also be seen in patients with negative SeHCAT test results, suggesting that the test may not be perfect in predicting treatment response 3, 4.

Prevalence of Bile Acid Malabsorption in Chronic Diarrhea

• Bile acid malabsorption is a common cause of chronic diarrhea, occurring in up to one third of patients with functional characteristics 4.
• The 75SeHCAT test is the gold standard for diagnosing bile acid malabsorption, and can help identify patients who may benefit from cholestyramine treatment 4, 5.
• Systematic investigation of bile acid malabsorption should be included in the diagnostic algorithms of patients with chronic watery diarrhea 4.