Overview of Bile Acid Resins

February 1, 2021

At the beginning of my career, all we had to lower cholesterol was diet, exercise, and cholestyramine (Questran®).  One of my colleagues had a heart attack at the age of 42 years.  His wife went to a cooking school in the early 1980s to learn how to cook heart-healthy meals.
The statins came along about 1987 and for the most part, displaced cholestyramine as treatment of hyperlipidemia. Now I see that most of the cholestyramine prescriptions are written by gastroenterologists, and the colesevelam prescriptions are written by endocrinologists!

When you’re finished reading, scroll to the bottom of the page to access your free micro-learning CE credit course!
0.25 ce credits

Mechanism of Action:
Anion exchange resin that binds bile acids in the intestine.  Resins are insoluble and non-absorbable.  Bile acids are synthesized from cholesterol, and by their removal, more cholesterol is taken up from the bloodstream.  Bile acids and resins are excreted in the stool.
Indication: Usually used as adjuncts to statin therapy requiring further lowering of LDL, reduces LDL by 15-30%.
Warnings/ Precautions/Adverse effects:

  • Constipation- major side effect (30%)
  • Taken right before meals.
  • ELEVATES Triglycerides (negative feedback with liver)
  • Vitamin deficiencies: Bind fat-soluble vitamins (A, D, E, K); be sure to monitor for Vitamin-K deficiency

Drug interactions:

  • Will bind other drugs and decrease their absorption. Colestipol and cholestyramine bind digoxin, warfarin, statins, and other ionic charged drugs can be bound.
  • Other drugs should be taken 1 hour before, or 4-6 hours after the resins

Patient Education:

  • Other drugs should be taken 1 hour before, or 4-6 hours after the resins.
  • Increase fluid intake and fiber in order to better cope with constipation
  • Large tablet load, unpalatable taste, and side effects will impact adherence to this class of drugs.

Products of this Class:

  • Cholestyramine (Questran®, Prevalite®) available in regular and sugar-free.  Scoop is included.
    • Dose = 4gm 1 –2 times daily
    • Dissolve granules in water or juice.
  • Colestipol (Colestid®)
    • Tablets (1gm): 2 to 16 tablets daily
    • Granules: 5gm packets,  5 to 30gm/day
  • Colesevelam (Welchol® 625mg)
    • Also used as add-on therapy for Type-2 diabetes. Used along with Metformin, sulfonylureas, and insulin. Bile acids play a role in cholesterol and glucose metabolism (FXR receptor). Reducing bile acid absorption can improve both.
      Lowers HbA1c about 0.5%- 0.8%; Lowers LDL up to 20%.
    • CAUTION:  in patients with triglycerides over 300 mg/dL. Avoid use if triglycerides exceed 500 mg/dL. May increase triglycerides up to 10% especially when combined with insulin or sulfonylureas.
    • Dose: 3 tablets BID or 6 tablets as a single dose or 3.75gm packets once daily.
    • Colesevelam does NOT bind digoxin, warfarin, or statins.
0.25 ce credits

Pruritus may develop in patients with cholestasis due to any cause. Elevated bile acids in the skin can cause itching. Cholestyramine (4-16 grams per day) can be considered as first line therapy. Colestipol can also be considered. Best if dosed before and after breakfast in patients with an intact gallbladder to enhance the excretion of the bile pruritogens, which seem to accumulate in the gallbladder during the overnight fast.
Cholestyramine binds toxins A and B excreted by Clostridium difficile.  Cholestyramine does not alter the gut flora but may be helpful as adjunctive therapy.  Now that vancomycin is considered first line therapy for C. dif, caution must be exercised when using cholestyramine, as it may bind vancomycin rendering it less effective.  If both are given together, be sure to separate by at least 2-3 hours.
Some diaper rash compounds include cholestyramine to bind up bile acids, which can cause direct irritation. Nationwide Children’s Hospital uses a 20% Cholestyramine/Petrolatum preparation, consisting of cholestyramine light (80%) [25grams] combined with petrolatum base [75grams]. Shelf life was 180 days.
Have a Great Day on the Bench!!