Questran
Questran
Generic Name
Questran
Mechanism
Questran (cholestyramine) is a *bile acid sequestrant* that acts in the gastrointestinal lumen.
• Binds bile acids: It has a high affinity for bile acids (cholic, chenodeoxycholic, etc.) forming an insoluble complex.
• Prevents reabsorption: The complex is excreted in feces, reducing the enterohepatic recycling of bile acids.
• Decreases hepatic cholesterol synthesis: Loss of bile acids triggers up‑regulation of LDL‑receptor expression on hepatocytes, lowering plasma LDL‑cholesterol and other atherogenic lipids.
• Reduces intestinal calcium binding: The complex may bind dietary Ca²⁺, contributing to lipid‑soluble vitamin malabsorption and causing pruritus relief in cholestasis.
Pharmacokinetics
- Absorption: Virtually none; acts entirely in the GI tract.
- Distribution: Not measurable in plasma.
- Metabolism: None (non‑systemic).
- Elimination: Excreted unchanged in feces within 24–48 h.
- Half‑life: Not applicable; pharmacological effect lasts while the drug remains bound to bile acids.
Indications
- Hyperlipidemia:
- Primary or secondary hypercholesterolemia (≥4 g/day, up to 12 g/day).
- Adjunct to statins when LDL goals are unmet.
- Cholestatic pruritus:
- Primary biliary cholangitis, intrahepatic cholestasis of pregnancy, drug‑induced cholestasis.
- Gallstone prophylaxis:
- Post‑cholecystectomy patients for ~6 months (4 g/day).
- Irritable bowel syndrome (IBS) & acidic stool:
- Off‑label for diarrhea or steatorrhea.
Contraindications
- Severe or symptomatic gastrointestinal obstruction, ileus, or a closed bowel loop.
- PHOBIA to polysorbate 80 (in the soft‑gel formulation).
- Pregnancy: Category C; use only if the benefit outweighs risks.
- Suspected or known protein‑losing enteropathy.
- Renal failure: Not specifically contraindicated, but monitor for electrolyte shifts due to hypocalcemia.
Dosing
| Condition | Typical Dose | Frequency | Notes |
| Hyperlipidemia | 4 g capsule (soft‑gel) | 1–4 capsules/day | Max 12 g/day |
| Cholestatic pruritus | 4 g | 1–4 capsules/day | Dose titrated to relief |
| Gallstone prophylaxis | 4 g | 1 cap/day | Until 6 months post‑surgery |
| Off‑label diarrhea | 1–4 capsules | PRN | Start with 1 cap |
• Take with: Water or non‑fatty drinks.
• Timing: Separate from oral meds by ≥4 h to prevent drug sequestration.
• Rotary: If using the powder, add to water/juice; allow to stand 30 min before ingestion to allow full binding.
Adverse Effects
| Adverse Effect | Frequency | Notes |
| Constipation | Common | Use lactulose or polyethylene glycol if needed |
| Diarrhea | Common | Usually mild, self‑limited |
| Abdominal cramping | Common | Monitor if severe |
| Nausea, flatulence | Common | Adjust meal timing |
| Fatigue | Rare | Evaluate medication schedule |
| Serious | ||
| Hypocalcemia | Rare | Check Ca²⁺ if symptoms |
| Vitamin K deficiency → coagulopathy | Rare | Monitor INR if on warfarin |
| Severe allergic reaction (rash, anaphylaxis) | Rare | Avoid in polysorbate‑80 allergy |
| Intestinal obstruction | Very rare | Evaluate if abdominal distension |
Monitoring
- Baseline & quarterly lipid profile (total cholesterol, LDL‑C, HDL‑C, TG).
- Full blood count & liver function tests (LFTs) annually (monitor for hepatic dysfunction).
- Vitamin D and calcium every 6 months if on long‑term therapy.
- Warfarin patients: INR every 2–3 days when starting/altering dose.
- Pregnancy: Routine obstetric monitoring.
Clinical Pearls
1. Drug Separation Is Critical – Cholestyramine’s binding capacity can sequester nearly any orally administered drug. Separate by at least 4 h; for non‑oral meds, separate by ≥8 h.
2. Flatulence vs. Constipation – Starting at 1 cap/day and gradually up‑titrating reduces GI upset and allows tolerance.
3. Use a “carry‑off” window for fat‑soluble vitamins – Give vitamins or multivitamin ≥2 h after cholestyramine to assure absorption.
4. Caution in Elderly – Aging may reduce gastric motility, raising constipation risk; consider adding bulk laxatives.
5. Gallstone Prophylaxis – Single‑dose daily (4 g) for 6 months post‑cholecystectomy is more likely to be adhered to and effectively reduces gallstone recurrence.
6. Hydroporic Relief – In cholestasis, beholding Questran helps relieve pruritus by sequestering bile salts that act as pruritogens.
7. Rapid Onset of Lipid Reduction – Clinical trials demonstrate significant LDL decrease within 3–4 weeks; adjust statin therapy early to avoid unnecessary side effects.
8. Pregnancy Safety – Animal studies meet Category C; some small clinical studies indicate no teratogenicity, yet fetal safety is not guaranteed—obtain informed consent.
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• References (for further reading)
1. *DrugBank – Cholestyramine*
2. *Katzung & Trevor’s Basic & Clinical Pharmacology*
3. UpToDate: “Cholestyramine: β‑blockers for pruritus”
4. FDA label, *United States* – Questran (Cholestyramine)
*Prepared for quick reference by medical students and healthcare professionals.