Contraindications and Precautions for Cholestyramine Use

Absolute Contraindications

• The American College of Cardiology recommends avoiding cholestyramine in patients with a history of serious hypersensitivity reaction to cholestyramine or its components, as it is an absolute contraindication 1

Critical Precautions and Relative Contraindications

• The American College of Cardiology advises against using cholestyramine in patients with gastroparesis, other GI motility disorders, or history of major GI tract surgery with risk for bowel obstruction, as it can cause or worsen GI obstruction 1
• Cholestyramine is contraindicated when triglycerides exceed 500 mg/dL due to risk of hypertriglyceridemia-induced pancreatitis, according to the American College of Cardiology 1
• The American College of Cardiology recommends that warfarin be taken at least 1 hour before or 4-6 hours after cholestyramine, with frequent INR monitoring during initiation and periodically thereafter, as cholestyramine significantly increases bleeding risk in patients on warfarin 1
• The American College of Cardiology suggests that digoxin should be taken at least 1 hour before or 4-6 hours after cholestyramine, as cholestyramine decreases digoxin bioavailability and can reduce therapeutic levels 1
• The American College of Cardiology recommends that thyroid medications be taken at least 1 hour before or 4-6 hours after cholestyramine, as cholestyramine significantly impairs absorption of thyroid hormones 1
• The American College of Cardiology advises strict timing separation (1 hour before or 4-6 hours after cholestyramine) for medications such as oral contraceptives, phenytoin, thiazide diuretics, propranolol, phenylbutazone, tetracycline, penicillin G, phenobarbital, estrogens, and progestins, due to reduced absorption 1
• The American College of Cardiology recommends supplementing with water-miscible or parenteral forms of fat-soluble vitamins during chronic cholestyramine therapy, taken at least 4 hours before cholestyramine, to prevent deficiencies of fat-soluble vitamins (A, D, E, K) and folate 1
• Before prescribing cholestyramine, the American College of Cardiology recommends verifying that triglycerides are less than 500 mg/dL and that there is no history of bowel obstruction, gastroparesis, or major GI surgery 1

Cholestyramine Administration and Interaction Guidelines

Critical Drug Interaction Management

• The American College of Cardiology and Clinical Gastroenterology and Hepatology guidelines recommend that all other medications must be taken at least 1 hour before or 4-6 hours after cholestyramine to prevent impaired absorption, particularly for medications such as thyroid hormone, warfarin, oral contraceptives, phenytoin, digoxin, antibiotics, and diuretics 2, 3
• The American College of Cardiology recommends taking critical medications first thing in the morning on an empty stomach, waiting at least 1 hour, and then taking cholestyramine 30 minutes before breakfast, and taking evening medications at bedtime (4+ hours after dinner-time cholestyramine dose) 2, 3
• The American College of Cardiology guidelines state that warfarin requires frequent INR monitoring during initiation when taken with cholestyramine 3
• The American College of Cardiology and Clinical Gastroenterology and Hepatology guidelines recommend taking fat-soluble vitamin supplementation (A, D, K) 4+ hours before cholestyramine if needed, and routine vitamin K monitoring is not consensus-recommended, but checking prothrombin time periodically may be prudent 2, 3

Common Pitfalls to Avoid

• The American College of Cardiology reports that constipation, dyspepsia, and nausea are the most common adverse effects of cholestyramine, and recommends strategies to minimize them 3

Key Contraindications

• The American College of Cardiology guidelines state that cholestyramine is contraindicated in patients with complete biliary obstruction or history of serious hypersensitivity 3