Cholestyramine Dosing
For adults, start cholestyramine at 4 grams once or twice daily and titrate up to 8-24 grams per day in divided doses; for pediatric patients, use 240 mg/kg/day (not exceeding 8 g/day) divided into 2-3 doses. 1
Adult Dosing
The FDA-approved dosing allows for flexible administration:
- Starting dose: 4 grams once or twice daily
- Maintenance range: 8-24 grams per day
- Dosing frequency: Can be given as a single daily dose (12-16 g), twice daily (for doses ≥24 g), or traditionally three times daily 1
Important: Research demonstrates that single daily dosing is as effective as traditional three-times-daily administration, achieving 21.6% cholesterol reduction with once-daily dosing versus 25.6% with three-times-daily dosing 2. For larger doses (24 g/day), splitting into twice-daily administration is more practical due to volume considerations 2.
Pediatric Dosing
The standard pediatric dose is 240 mg/kg/day of anhydrous cholestyramine resin, divided into 2-3 doses, with a maximum of 8 g/day 1.
Key pediatric considerations:
- Dosing should be titrated based on response and tolerance 1
- Studies in children with familial hypercholesterolemia used 8-24 g/day (0.3-1.1 g/kg/day), achieving 36% cholesterol reduction 3
- Twice-daily dosing is effective and may improve compliance compared to three-times-daily regimens 3, 4
- The dose required correlates directly with pretreatment cholesterol levels, not body weight 4
Critical Timing Considerations
Administer other medications at least 1 hour before or 4-6 hours after cholestyramine to avoid drug binding and reduced absorption 1. This is essential because cholestyramine can bind numerous medications including thyroid preparations, warfarin, digoxin, and oral contraceptives 5, 1.
Monitoring Requirements During Long-Term Use
While routine annual monitoring lacks strong consensus 5, consider:
- Fat-soluble vitamin supplementation (A, D, E, K) during long-term therapy, particularly vitamin D which commonly decreases 1, 6
- Folate monitoring and supplementation, as deficiency can occur even with low doses 6
- Periodic INR monitoring may be prudent given rare reports of vitamin K deficiency causing coagulopathy 5
Common Pitfalls
- Do not start cholestyramine within 3 months of abdominal surgery in children due to one reported case of intestinal obstruction 6
- Expect gastrointestinal side effects (constipation most common); these are dose-related but rarely require discontinuation 1, 6
- Growth is not adversely affected in children on appropriate dosing 3, 6