Cholestyramine for Diarrhea

A Drug to Lower Cholesterol May Also Help Chronic Diarrhea

In This Article
Man runs to bathroom toilet on date
Peter Cade / Getty Images

Cholestyramine is a medication primarily prescribed to lower cholesterol. However, because of its effects on bile acid, it sometimes is prescribed as a treatment for chronic cases of diarrhea. If your doctor has prescribed cholestyramine for you, or you have chronic diarrhea and wonder whether it may help you, this overview will cover basic information about the drug and its effects.

Brand Names

Cholestyramine is sold under a variety of names:

  • Cholybar
  • Locholest
  • Locholest Light
  • Prevalite
  • Questran
  • Questran Light

How It Works

Cholestyramine is classified as a bile acid binder or sequestrant. It works by attaching itself to bile acids within the digestive tract so that they pass from the body. If you have high cholesterol, this reduction of bile acids triggers your body to convert blood cholesterol into bile acids, which has the effect of reducing the levels of cholesterol in your blood.

If you have a condition known as bile acid malabsorption (BAM), the medication reduces the action of bile acids in the large intestine, which has the effect of reducing diarrhea symptoms.


Cholestyramine is available in either a powder form or as a chewable bar. The powder form can be mixed with water, juice, or milk, or mixed into soft foods, such as pureed fruit or soup. If you use the bar form, be sure to drink plenty of water. Be sure to take the medication as prescribed and do not stop taking it without your doctor's permission.

Who Shouldn't Take It

Tell your doctor if you are pregnant or breastfeeding or have any chronic health problem. Cholestyramine can have an effect on the absorption of other medications, so be sure to tell your doctor what other medications you are currently taking.

Side Effects

As you can see, the following two most commonly reported side effects of cholestyramine are digestive in nature and should ease as your body gets used to the medication. The change in the appearance of your stool is to be expected as the drug removes bile acids from your digestive tract.

  • Black, tarry stools
  • Stomach pain

The following side effects may also occur:

  • Bloating
  • Diarrhea
  • Dizziness
  • Gas
  • Headache   

The good news is that these side effects may go away during treatment as your body adjusts to the medicine. Check with your health care professional if any of the above side effects are persistent or bothersome or if you have any questions about them. Your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Call your doctor immediately if you experience:

  • Rectal bleeding
  • Severe abdominal pain
  • Sudden loss of weight
  • Vomiting

Further Research

As stated above, cholestyramine is a medication for BAM, which causes symptoms of chronic diarrhea. Some researchers are investigating whether an idiopathic form of BAM (I-BAM) might be the reason behind some cases of IBS, particularly for people who experience diarrhea immediately after eating or people who have had their gallbladders removed.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Barkun AN, Love J, Gould M, Pluta H, Steinhart H. Bile acid malabsorption in chronic diarrhea: pathophysiology and treatment. Can J Gastroenterol. 2013;27(11):653-9. doi:10.1155/2013/485631

  2. ChemIDplus - 11041-12-6 - Cholestyramine resin [USP]. Similar structures search, synonyms, formulas, resource links, and other chemical information. U.S. National Library of Medicine.

  3. Sweeney ME, Fletcher BJ, Rice CR, et al. Efficacy and compliance with cholestyramine bar versus powder in the treatment of hyperlipidemia. Am J Med. 1991;90(4):469-73.

  4. Riaz S, John S. Cholestyramine Resin. [Updated 2019 Sep 30]. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. 

Additional Reading
  • "Cholestyramine (Oral Route)." Mayo Clinic 
  • "Cholestyramine Resin." Medline Plus 
  • Pattni, S. & Walters, J. "Recent advances in the understanding of bile acid malabsorption." British Medical Bulletin 2009 92:79-93.
  • Wedlake, L., "Systematic review: the prevalence of idiopathic bile acid malabsorption as diagnosed by SeHCAT scanning in patients with diarrhoea-predominant irritable bowel syndrome." Alimentary Pharmacology and Therapeutics 2009 30:707-717.