What is the dosage and administration of cholestyramine powder for treating high cholesterol?

Cholestyramine Powder: Dosage and Administration for High Cholesterol

For treating high cholesterol in adults, start with 4 grams of cholestyramine resin once or twice daily, then titrate to a maintenance dose of 8-16 grams daily divided into two doses, with a maximum of 24 grams daily. 1

Starting Dose and Titration

• Initial dose: 1 pouch or 1 level scoopful (containing 4 grams anhydrous cholestyramine resin) once or twice daily 1
• Maintenance dose: 8-16 grams daily divided into two doses 2, 1
• Maximum dose: 24 grams daily (6 pouches or scoopfuls) 1
• Increase doses gradually with lipid/lipoprotein assessment at intervals of at least 4 weeks 1

Timing and Administration

• Administer at mealtime, though timing can be modified to avoid interference with other medications 1
• The medication may be given in 1 to 6 divided doses per day, though twice daily is standard 1
• Never take in dry form—always mix powder with at least 2-3 ounces of water or non-carbonated beverage 1
• Can be mixed with highly fluid soups or pulpy fruits like applesauce or crushed pineapple 1

Expected Efficacy

• Monotherapy: Achieves 10.4% LDL-C reduction versus placebo 2
• Dose-ranging studies show 16.3%, 22.8%, and 27.2% LDL-C reductions with 5g, 10g, and 15g daily doses respectively 2
• When combined with low- to moderate-intensity statins, provides an additional 10-16% LDL-C reduction 2
• The majority of lipid-lowering effect occurs within 14 days of therapy 3

Critical Drug Interactions and Spacing

• All other medications must be taken at least 1 hour before or 4 hours after cholestyramine to prevent impaired absorption 2
• This is particularly critical for: cyclosporine, oral contraceptives, olmesartan, phenytoin, sulfonylureas, thyroid replacement therapy, and warfarin 2
• UDCA (ursodeoxycholic acid) must be spaced at least 4 hours away from cholestyramine 2
• For warfarin patients, monitor INR frequently during initiation and periodically thereafter 2

Common Adverse Effects and Management

• Gastrointestinal effects: Constipation, dyspepsia, and nausea are most common 2
• Vitamin deficiencies: May cause vitamin K and fat-soluble vitamin deficiencies; supplement oral vitamins at least 4 hours before cholestyramine 2
• Triglyceride elevation: Monitor triglycerides as cholestyramine can increase levels and potentially cause pancreatitis 2, 3
• Rare but serious: bowel obstruction, fecal impaction, esophageal obstruction 2

Contraindications and Precautions

• Absolute contraindications: Complete biliary obstruction, history of serious hypersensitivity, triglycerides >500 mg/dL, history of hypertriglyceridemia-induced pancreatitis, bowel obstruction 2
• Avoid in patients with gastroparesis or other GI motility disorders 2
• Avoid in patients with history of major GI tract surgery with risk for bowel obstruction 2

Special Populations

Pediatric Use

• For children 10-17 years with heterozygous familial hypercholesterolemia: 8-16 g/day orally divided into 2 doses 2
• Use as monotherapy or in combination with statin when LDL-C remains ≥190 mg/dL or ≥160 mg/dL with positive family history of premature CVD 2
• Supplement folate and vitamin D due to documented reductions during therapy 2

Pregnancy and Lactation

• Considered safe to use during pregnancy and lactation 2
• For cholestasis-associated pruritus in pregnancy: 4-16 g daily in divided doses, separated from other medications by at least 2 hours 2
• Monitor PT/INR regularly as cholestyramine may exacerbate vitamin K deficiency in cholestatic patients 2

Cardiovascular Outcomes Evidence

• The LRC-CPPT trial demonstrated a 19% reduction in risk (p<0.05) of definite CHD death and/or definite nonfatal MI in 3,806 asymptomatic middle-aged men treated for an average of 7.4 years 2
• This remains the only bile acid sequestrant with proven cardiovascular mortality benefit 2

Practical Considerations

• High pill burden and poor palatability are major barriers to compliance 2
• Confectionery bar formulation shows equivalent efficacy to powder but offers no compliance advantage and may have slightly more GI side effects 3
• Single daily dosing may be as effective as divided dosing and can improve compliance 4
• When combined with HMG-CoA reductase inhibitors, lipid-lowering effects are enhanced 1