II. Indications

  1. Hyperlipidemia adjunctive management (rare use)
  2. Cholestyramine is also used off-label (not FDA approved)
    1. Cholestasis associated Pruritus
    2. Diarrhea Dominant Irritable Bowel Syndrome

III. Contraindications

  1. Absolute
    1. Serum Triglycerides >500 mg/dl (bile acid resins increase Triglycerides)
    2. Bowel Obstruction
    3. Complete biliary obstruction
  2. Relative
    1. Triglycerides >200 to 300 mg/dl

IV. Mechanism

  1. Binds bile salts
    1. Results in insoluble complexes that are excreted in the stool
    2. Reflex in-vivo response
      1. LDL receptors are increased
      2. Additional bile acids are generated via Cholesterol oxidation
  2. Effects
    1. LDL Cholesterol decreased (15-30%)
    2. HDL Cholesterol increased (3-5%)
    3. Triglycerides increased (10 to 15%)

V. Medications

  1. Cholestyramine (Questran)
  2. Colestipol (Colestid)
  3. Colesevelam (Welchol)
    1. Most expensive agent of the class
    2. May be preferred agent of class
      1. Lower adverse effect profile (see above)
      2. May be taken concurrently with Statin
      3. Lowers A1C by 0.5%
      4. Zieve (2007) Clin Ther 29(1):74-83 [PubMed]

VI. Drug Interactions

  1. Each binding resin has specific guidelines for timing other medications to reduce interactions
  2. Most stringent guidelines are to avoid medications 2 hours before or 4 hours after binding resin
  3. Take with water or orange juice before meals
  4. Binding resins may also interfere with other lipid lowering agents (e.g. Statins, Ezetimibe)
    1. Colesevelam appears to have less effect on other lipid lowering agent levels
  5. Binding resins interfere with fat soluble Vitamin Absorption
    1. Take Vitamins 2 hours before or 4 hours after Resin
    2. Colesevelam does not appear to significantly affect Vitamin Absorption

VII. Efficacy

  1. Lowers cardiovascular mortality by 30%
  2. Reduces Myocardial Infarction risk
    1. Eggertsen (1984) JAMA 251(3):349-50 [PubMed]

VIII. Adverse Effects

  1. Gastrointestinal (GI)
    1. Constipation
    2. Flatulence
    3. Dyspepsia
  2. Methods to reduce adverse GI side effects
    1. Use moderate doses: 8-10 g per day
    2. Increase Dietary Fiber or supplement with Psyllium
    3. Colesevelam may have less GI intolerance

IX. Safety

  1. Bile acid resins are not absorbed, but may affect Vitamin Absorption in pregnancy
  2. Pregnancy Category C (for Cholestyramine) and Category B for Colestipol and Colesevelam
  3. Considered Safe in Lactation (not found in Breast Milk)

X. References

  1. (2022) Non-StatinLipid Lowering Agents, Presc Lett, Resource #380202
  2. (2022) Med Lett Drugs Ther 64(1659): 145-52
  3. (2000) Med Lett Drugs Ther 42:102-4 [PubMed]

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