CHOLESTYRAMINE LIGHT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CHOLESTYRAMINE LIGHT (CHOLESTYRAMINE LIGHT).
Binds bile acids in the intestine, forming an insoluble complex that is excreted in feces, thereby preventing enterohepatic recirculation of bile acids and promoting hepatic conversion of cholesterol to bile acids, reducing serum LDL-cholesterol.
| Metabolism | Not metabolized; acts locally in the gastrointestinal tract and is excreted unchanged in feces. |
| Excretion | Primarily fecal as bile acid complex; <0.05% renal excretion of unchanged drug; negligible systemic absorption. |
| Half-life | Not applicable; cholestyramine is not absorbed systemically and has no plasma half-life; clinical effect duration reflects gastrointestinal transit time. |
| Protein binding | Not applicable (non-absorbed); no plasma protein binding. |
| Volume of Distribution | Not applicable (non-absorbed); confined to gastrointestinal lumen. |
| Bioavailability | Oral: <0.04% (minimal systemic absorption due to large molecular weight and quaternary ammonium structure). |
| Onset of Action | Oral: Reduction in pruritus occurs within 1-3 weeks; lipid-lowering effect begins within 24-48 hours with maximal effect in 1-2 weeks. |
| Duration of Action | Lipid-lowering effect persists as long as drug is taken; pruritus relief lasts for duration of therapy; rebound may occur upon discontinuation. |
| Molecular Weight | The molecular weight of cholestyramine resin varies; the monomer unit (styrene-divinylbenzene copolymer with trimethylbenzylammonium groups) has a molecular weight of approximately 1,000,000 Da for the polymer. |
4 g orally once or twice daily, increased gradually to 4 g 1-6 times daily; maintenance 4-24 g/day in divided doses.
| Dosage form | POWDER |
| Renal impairment | No dosage adjustment required for renal impairment. |
| Liver impairment | No specific dosage adjustment recommended; caution in patients with severe hepatic impairment. |
| Pediatric use | 240 mg/kg/day orally in 2-3 divided doses, not to exceed 8 g/day; adjust based on clinical response. |
| Geriatric use | Start at low end of dosing range (4 g/day) and titrate slowly; monitor for constipation and drug interactions. |
| 1st trimester | Cholestyramine is not absorbed systemically, so fetal exposure is minimal. However, use only if clearly needed due to potential for fat-soluble vitamin deficiency. |
| 2nd trimester | Minimal systemic absorption; theoretical risk of vitamin K deficiency leading to neonatal hemorrhage. Monitor prothrombin time and supplement vitamins as needed. |
| 3rd trimester | Can cause maternal vitamin K deficiency, increasing risk of neonatal hemorrhage. Administer parenteral vitamin K to neonate at delivery if mother used cholestyramine. |
Clinical note
Comprehensive clinical and safety monograph for CHOLESTYRAMINE LIGHT (CHOLESTYRAMINE LIGHT).
| Placental transfer | Minimal to no placental transfer; cholestyramine is a large, quaternary ammonium anion exchange resin that is not absorbed from the gastrointestinal tract. |
| Breastfeeding | Cholestyramine is not absorbed systemically, so it is unlikely to appear in breast milk. However, it may interfere with maternal absorption of fat-soluble vitamins, potentially affecting milk composition. Monitor infant for signs of vitamin deficiency and consider supplementing mother with vitamins. |
■ FDA Black Box Warning
No FDA boxed warning.
| Serious Effects |
Complete biliary obstructionHypersensitivity to cholestyramine or any component of the formulation
| Precautions | May reduce absorption of fat-soluble vitamins (A, D, E, K), requiring supplementation, May cause hyperchloremic metabolic acidosis, especially in children with large doses, May cause constipation, which can aggravate hemorrhoids; discontinue if impaction occurs, May interfere with absorption of other drugs; administer other medications at least 1 hour before or 4-6 hours after cholestyramine, Use with caution in patients with phenylketonuria (products may contain aspartame) |
| Food/Dietary | Cholestyramine binds to bile acids in the gut and can also bind to dietary fats and fat-soluble vitamins. Administer with food to reduce GI side effects. High-fat meals may reduce efficacy by competing for binding. Avoid concurrent intake with grapefruit juice (may alter binding). Separate ingestion from high-fat, large meals by at least 1 hour. |
Loading safety data…
| Lactation Rating | L1 - Safe |
| Teratogenic Risk | Cholestyramine is a non-absorbed resin; systemic absorption is negligible. No teratogenic effects reported in animal studies or human case reports. Risk to fetus is minimal across all trimesters. |
| Fetal Monitoring | Monitor maternal lipid levels and fat-soluble vitamin status (A, D, E, K) during prolonged use in pregnancy. Fetal monitoring: standard antenatal care. |
| Fertility Effects | No known adverse effects on fertility. Cholestyramine may interfere with absorption of folic acid, but no direct impairment of reproductive function reported. |
| Clinical Pearls | Cholestyramine Light contains aspartame; contraindicated in phenylketonuria. Administer other medications at least 1 hour before or 4-6 hours after cholestyramine to reduce binding. Monitor for hyperchloremic metabolic acidosis, especially in renal impairment. Constipation is common; encourage fluid intake. May reduce absorption of fat-soluble vitamins (A, D, E, K); consider supplementation. |
| Patient Advice | Take exactly as prescribed, usually mixed with water or non-carbonated liquid; do not swallow dry powder. · Take other medications at least 1 hour before or 4-6 hours after cholestyramine to ensure proper absorption. · Drink plenty of fluids and eat fiber-rich foods to prevent constipation. · Report unusual bleeding, bruising, or dark urine (signs of vitamin K deficiency). · This product contains aspartame; avoid if you have phenylketonuria. |