Bile Acid Sequestrants: Everything You Need to Know

These medications can help lower cholesterol levels

Bile acid sequestrants, also known as bile acid resins or BARs, are a class of medications used to help lower your cholesterol levels. If your cholesterol is high, your healthcare provider may decide to add a bile acid sequestrant to your cholesterol-lowering regimen.

Currently, three bile acid sequestrant drugs are available in the United States:

Welchol (colesevelam) and Colestid (colestipol) are available as tablets or resin powder. Prevalite (cholestyramine) is available only as resin powder. All are also available as generic drugs.

This article discusses how bile acid sequestrants work, the common side effects, and who shouldn't take them.

A woman suffering from GI symptoms

PhotoAlto / Alix Minde / Getty Images 

How They Work

Bile acid sequestrants work by binding to bile acids and preventing the absorption of bile acids from the small intestine. Instead of being absorbed into the blood, the combination of bile acids and the drug is excreted in the feces.

In response to lowered bile acids in the body, your liver will convert cholesterol into more bile acids. Additionally, LDL receptors will also be increased in the liver. These actions help lower cholesterol levels in the blood.

As a result, bile acid sequestrants mainly lower LDL cholesterol between 15% to 30% and only slightly raise HDL cholesterol.

These drugs do not appear to affect triglyceride levels but, in some cases, bile acid sequestrants may actually raise your triglycerides if taken for a long period of time. Because they have not been proven to lower the risk of a heart attack or stroke, bile acid sequestrants are not as commonly prescribed as other cholesterol-lowering medications, especially statins. However, they can be taken alone or combined with other cholesterol-lowering medications to help you manage your lipid levels.

Common Side Effects

Side effects from taking bile acid sequestrants mostly consist of gastrointestinal problems, including:

  • Nausea
  • Constipation
  • Bloating
  • Flatulence

The side effects can be managed by increasing your fluid intake, taking a stool softener or by adding fiber to your diet.

Some people may find it difficult to consistently take their bile acid sequestrant. For instance, some individuals might find the resins to be too gritty to taste—especially if they have to take them more than one time a day.

Although there are ways to improve the taste of the resins, some taking the drug still cannot tolerate their taste. Additionally, the Welchol tablet is large and may be difficult to swallow for some people. If you have been prescribed a bile acid sequestrant and are having difficulty taking your medication, you should let your healthcare provider know of this.

Who Should Not Take a Bile Acid Sequestrant

Some people shouldn't take a bile acid sequestrant. Tell your healthcare provider if you have any of these other medical conditions below:

  • If you already have very high triglyceride levels or have ever experienced medical issues due to very high triglycerides, such as pancreatitis. This is due to the fact that bile acid sequestrants may raise your triglyceride levels further.
  • Bile acid sequestrants may interact with some vitamins or other medications that you are taking. Therefore, you should notify all of your healthcare providers if you are taking a bile acid sequestrant so that they can make sure that the drug is not interacting with any other medications, vitamins, or supplements that you are taking. In some cases, your healthcare provider may request that you increase the amount of time between taking your bile acid sequestrant and other medications.
  • Bile acid sequestrants have not been studied in women who are breastfeeding or pregnant. Although bile acid sequestrants do not appear to cross into the bloodstream, they can limit the absorption of certain important vitamins.
  • If you have gastrointestinal conditions, such as hemorrhoids or constipation, taking bile acid sequestrants may worsen these conditions. Additionally, you should let your healthcare provider know if you have ever had a bowel obstruction.

Your healthcare provider will weigh the benefits and risks of prescribing a bile acid sequestrant for you in these instances to help you manage your lipids.

Frequently Asked Questions

  • What do bile acid sequestrants do?

    Bile acid sequestrants block bile acid in the stomach from being absorbed in the bloodstream. Bile acids are formed in the liver from cholesterol. By blocking their absorption, the liver draws cholesterol out of the blood, which in turn lowers cholesterol levels. 

  • When do you use bile acid sequestrants?

    Bile acid sequestrants are primarily prescribed to lower LDL cholesterol levels. They are also prescribed to treat:

    • Diarrhea caused by bile acid
    • Hyperthyroidism
    • Liver diseases including cirrhosis 
    • Pruritus, or itchy skin, that is caused by bile acids accumulating in the skin
    • Type 2 diabetes
  • How do you reduce bile acids naturally?

    How you eat can have an impact on the amount of bile acid your body produces. Avoid high-fat foods, including deep-fried food, fatty cuts of meat, and full-fat dairy, which increase bile acid production.

    Eat food rich in soluble fiber, which helps to absorb bile acids. Soluble fiber is found in barley, beans, lentils, nuts, oat bran, peas, seeds, and some fruits and vegetables.

    Eating small but more frequent meals can also help to reduce bile acids naturally.

2 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. National Library of Medicine. Bile acid sequestrants for cholesterol.

  2. Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on the management of blood cholesterol: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019;139(25):e1082-e1143. doi:10.1161/CIR.0000000000000625

By Jennifer Moll, PharmD
Jennifer Moll, MS, PharmD, is a pharmacist actively involved in educating patients about the importance of heart disease prevention.