Medicine & USMLE

Bile Acid Sequestrants

Cardio Drugs - Lipid Lowering
  1. Fibrates
  2. Statins
  3. Ezetimibe
  4. Nicotinic Acid (Niacin)
  5. Bile Acid Sequestrants


Bile acid sequestrants, also called bile acid resins, are a class of lipid lowering drugs. Drug names to remember include colesevelam, cholestyramine, and colestipol.

These drugs work by blocking the intestinal reabsorption of bile acid and lowering LDL levels.

A side effect of bile acid sequestrants is the blocked absorption of oral medications in the intestines. As a result, these drugs have a lot of drug interactions and shouldn’t be taken at the same time as other medications. Bile acid sequestrants also block the intestinal absorption of fat soluble vitamins, so patients should increase their intake of vitamins A, D, E, and K. Since bile acid sequestrants can disrupt normal digestion, they commonly cause GI side effects such as constipation, nausea and vomiting, as well as bloating.

Remember that bile acid sequestrants can be combined with juice to improve the taste.

Key Points

  • Bile Acid Sequestrants (Bile Acid Resins)
    • Drug Names
      • Colestipol (Colestid)
      • Cholestyramine (Prevalite, Questran)
      • Colesevelam (Welchol)
    • Clinical Use
      • Lipid Lowering
        • Treats hypercholesterolemia by lowering cholesterol levels
        • Often used in combination with other cholesterol-lowering drugs (e.g., statins)
    • Mechanism
      • Prevent reabsorption of bile acids in the intestines
        • Increase excretion of bile acids in the feces
        • Liver compensates by converting cholesterol into new bile acids
        • Reduces cholesterol levels in the blood
      • Lower LDL
        • LDL stands for low-density lipoprotein
        • Often called “bad” cholesterol
    • Side Effects
      • Causes GI distress
        • Constipation
          • Patient should increase fiber and fluid intake
          • Laxative or stool softener may be needed
          • Not recommended with bowel obstruction or other GI disorders
        • Bloating
        • Nausea/Vomiting
        • Other GI side effects include abdominal pain, flatulence, and belching
        • These side effects are normal and expected
      • Decreases absorption of fat-soluble vitamins (A, D, E, K)
        • Patient should eat food high in in these vitamins and/or take vitamin supplements to prevent becoming deficient
      • Blocks absorption of oral medications
        • Includes oral contraceptives, levothyroxine, 2nd generation sulfonylureas, phenytoin, warfarin, thiazide diuretics, and digoxin
        • Do not take at the same time as other medications
          • Resources vary on the exact timing, but other oral medications should be taken several hours before or after taking a bile acid sequestrant
    • Nursing Considerations
      • Combine powder with juice to improve taste
        • Cholestyramine comes as a powder that is to be dissolved in liquid. Because of its bad taste, it is recommended to dissolve the powder in juice to improve its taste.