Cholestyramine Dosing Recommendations
The recommended starting dose of cholestyramine is 4 grams (one packet or scoop) once or twice daily, with a maintenance dose of 8-16 grams daily divided into two doses, and a maximum dose of 24 grams daily. 1
Standard Dosing Regimen
- Starting dose: 4 grams (one packet/scoop) once or twice daily 1
- Maintenance dose: 8-16 grams daily, divided into two doses 1
- Maximum dose: 24 grams daily (six packets/scoops) 1
- Dose titration: Increases should be gradual with lipid assessment at intervals of at least 4 weeks 1
Dosing Frequency Options
Cholestyramine can be administered flexibly from once daily to six times daily, though twice-daily dosing is the standard recommendation. 1
- Twice-daily administration is equally effective as four-times-daily dosing for the same total daily dose 2
- Single daily dosing of 12-16 grams achieves comparable cholesterol reduction to traditional three-times-daily regimens (21.58% vs 25.61% reduction) 3
- For doses of 24 grams daily, twice-daily administration is more practical due to volume considerations 3
Optimal Timing of Administration
The evening dose should be taken 30 minutes before the evening meal for maximum LDL-cholesterol reduction. 4
- Taking the p.m. dose 30 minutes before the evening meal produces significantly greater cholesterol reduction compared to mid-afternoon administration 4
- The suggested administration time is at mealtime, though this can be modified to avoid interference with other medications 1
Special Population Dosing
Chronic Kidney Disease
- No dosage adjustment is needed in CKD patients 5
Pruritus in Sclerosing Cholangitis
- Cholestyramine is not recommended as first-line therapy for pruritus in sclerosing cholangitis due to limited evidence and potential interference with UDCA absorption 5
- Bezafibrate or rifampicin are preferred for moderate to severe pruritus in this population 5
Hyperthyroidism (Adjunctive Therapy)
- Lower doses of 2-4 grams twice daily (4-8 grams total) are often effective and better tolerated as adjunctive therapy 6
Administration Guidelines
Always mix cholestyramine powder with at least 2-3 ounces of water or non-carbonated beverage; never take in dry form. 1
- Can be mixed with highly fluid soups or pulpy fruits like applesauce or crushed pineapple 1
- Critical drug interaction timing: Other medications must be taken at least 1 hour before or 4 hours after cholestyramine to avoid impaired absorption 1, 6
- High-risk medications requiring separation include thyroid hormones, warfarin, oral contraceptives, cyclosporine, phenytoin, and sulfonylureas 7
Expected Efficacy by Dose
The dose-response relationship for LDL-cholesterol reduction is well-established:
- 8 grams daily: Approximately 16-22% LDL-C reduction 7
- 16 grams daily: Approximately 23-27% LDL-C reduction 7, 3
- 24 grams daily: Approximately 27-28% LDL-C reduction 7, 3
Important Safety Considerations
Contraindications
Common Adverse Effects
- Gastrointestinal symptoms (constipation, dyspepsia, nausea) are most common 6, 1
- May increase triglyceride levels 6, 3
- Gradual titration minimizes GI side effects 1
Nutritional Monitoring with Long-Term Use
- Folate deficiency develops with prolonged treatment; oral folic acid 5 mg daily should be given to all patients on long-term therapy 8
- Fat-soluble vitamins (A, E, K) may decrease but typically remain in normal range 8
- Monitor prothrombin time and fat-soluble vitamin levels periodically 8
- Vitamin K deficiency can occur; oral vitamins should be administered at least 4 hours before cholestyramine 7
Special Warnings
- May increase TSH in patients receiving thyroid hormone replacement therapy 6
- Post-marketing reports include bowel obstruction, esophageal obstruction, and fecal impaction 6