QUESTRAN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for QUESTRAN (QUESTRAN).
Binds bile acids in the intestine, forming an insoluble complex that is excreted in feces, thereby preventing their enterohepatic reabsorption and increasing hepatic LDL receptor activity and cholesterol catabolism.
| Metabolism | Not absorbed systemically; acts locally in the gastrointestinal tract. |
| Excretion | Cholestyramine is not absorbed from the gastrointestinal tract; therefore, it is excreted entirely in the feces as the intact resin, with no renal or biliary excretion. |
| Half-life | Not applicable; the drug is not absorbed and does not have a systemic half-life. Clinical effect persists as long as the resin remains in the gut (approximately 6-8 hours per dose). |
| Protein binding | 0% (not absorbed, thus no systemic protein binding). The resin binds bile acids in the gut lumen. |
| Volume of Distribution | Not applicable; the drug is not absorbed and does not distribute into body tissues. Vd is effectively 0 L/kg. |
| Bioavailability | 0% (oral); cholestyramine is a non-absorbable resin, so it does not enter the systemic circulation. |
| Onset of Action | Oral: Reduction in serum LDL-cholesterol is typically observed within 24-48 hours, with maximal effect in 2-4 weeks. |
| Duration of Action | Duration of hypolipidemic effect: 2-4 weeks after initiation of therapy, effect persists as long as dosing continues. Upon discontinuation, serum lipids return to baseline within 1-2 weeks. |
| Molecular Weight | >1,000,000 Da (average molecular weight of cholestyramine resin) |
Questran (cholestyramine) is administered orally. The typical adult dose is 4 grams (one packet or one level scoop) once or twice daily, with a maximum of 24 grams per day. The powder should be mixed with at least 120 mL of fluid (e.g., water, juice).
| Dosage form | TABLET |
| Renal impairment | No dose adjustment is required for renal impairment. Cholestyramine is not systemically absorbed. |
| Liver impairment | No dose adjustment is required for hepatic impairment as cholestyramine acts locally in the gastrointestinal tract. |
| Pediatric use | For pediatric patients, the usual dose is 240 mg/kg/day orally in divided doses, not to exceed 8 grams per day. Dosing may be initiated at a lower dose and titrated upward based on response and tolerance. |
| Geriatric use | No specific dose adjustment is indicated for elderly patients. Use the standard adult dose, but consider potential for increased constipation and drug interactions due to polypharmacy. |
| 1st trimester | QUESTRAN (cholestyramine) is not absorbed systemically; however, it may interfere with absorption of fat-soluble vitamins (A, D, E, K) which are critical for fetal development. Use only if clearly needed, with monitoring of vitamin levels. |
| 2nd trimester | Same as T1. May reduce absorption of essential nutrients; supplement with fat-soluble vitamins and folate. Consider alternative therapies. |
| 3rd trimester | Same as T1. May cause neonatal bleeding due to vitamin K deficiency; administer vitamin K parenterally to mother before delivery if used near term. |
Clinical note
Comprehensive clinical and safety monograph for QUESTRAN (QUESTRAN).
| Placental transfer | Cholestyramine is a non-absorbable resin; it does not cross the placenta due to its high molecular weight and lack of systemic absorption. |
| Breastfeeding | Cholestyramine is not absorbed systemically and is unlikely to reach breast milk in significant amounts. However, it may reduce maternal absorption of fat-soluble vitamins, potentially affecting milk composition. Monitor infant for signs of vitamin deficiency. Generally considered compatible with breastfeeding. |
■ FDA Black Box Warning
Powder may cause severe esophageal and airway obstruction if inhaled or aspirated. Mix with water or other appropriate liquid before administration.
| Serious Effects |
Complete biliary obstructionHypersensitivity to cholestyramine or any component
| Precautions | May cause constipation and impact fecal impaction, especially in elderly; may reduce absorption of fat-soluble vitamins; may interfere with absorption of other drugs, including warfarin, thyroid hormones, and digitalis; hyperchloremic acidosis risk in patients with renal insufficiency. |
| Food/Dietary | Questran binds to bile acids and can interfere with absorption of fat-soluble vitamins. Take with food to reduce gastrointestinal upset. Avoid taking with high-fat meals if possible. Ensure adequate intake of vitamins A, D, E, K. Dietary fiber supplements (e.g., psyllium) should be taken separately. |
Loading safety data…
| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | Pregnancy Category C. Not systemically absorbed; minimal fetal exposure. No teratogenic effects observed in animal studies. Use only if clearly needed. |
| Fetal Monitoring | Monitor for fat-soluble vitamin deficiencies (A, D, E, K) and clotting times in mother and neonate if used long-term. |
| Fertility Effects | No known effect on fertility. May interfere with absorption of nutrients and medications; correct deficiencies to support reproductive health. |
| Clinical Pearls | Questran (cholestyramine) is a bile acid sequestrant used primarily for pruritus associated with partial biliary obstruction and hypercholesterolemia. It can cause or exacerbate hypertriglyceridemia. Administer other medications at least 1 hour before or 4-6 hours after Questran due to impaired absorption. Its gritty texture can be improved by mixing with pulpy fruits or juices. Monitor for fat-soluble vitamin deficiencies (A, D, E, K) with long-term use. |
| Patient Advice | Take exactly as prescribed; do not crush or chew the powder. · Mix the powder with at least 4-6 ounces of water, milk, juice, or applesauce; stir completely and drink immediately. · Do not take within 4-6 hours of other medications to avoid reducing their effectiveness. · Maintain a high-fiber diet to prevent constipation, a common side effect. · Report unusual bleeding or bruising, as it may indicate vitamin K deficiency. · Follow a low-fat diet as recommended by your healthcare provider. · Store at room temperature away from moisture. |