Colestyramine (Cholestyramine)
Brand names: Questran
Colestyramine (cholestyramine) is an oral anion-exchange bile-acid sequestrant used for bile-acid diarrhoea, pruritus associated with cholestasis or partial biliary obstruction, and as a lipid-lowering agent.
Adult dose
Dose adjustments
No dose adjustment is stated. §4.4 warns that prolonged use of colestyramine resin in high doses may produce hyperchloraemic acidosis, since it is the chloride form of an anion exchange resin — 'This is especially true in younger and smaller patients where the relative dosage may be higher as well as in patients with renal impairment.'
Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.
Contraindications
- Hypersensitivity to the active substance or to any of the excipients
- Complete biliary obstruction, since colestyramine cannot be effective where bile is not secreted into the intestine
- From §4.2: should not be used in children under 6 years — there are no data to support its use
- From §4.2: should not be used in patients with exudative or bloody diarrhoea
Side effects
- Constipation (very common) — usually mild and transient; predisposing factors when used as a cholesterol-lowering agent are high dose and age over 60 years; some patients require a temporary dose decrease or discontinuation
- Abdominal discomfort, flatulence, nausea, vomiting, diarrhoea, heartburn, dyspepsia and steatorrhoea (uncommon)
- Bleeding tendencies due to hypoprothrombinaemia (vitamin K deficiency), and vitamin A (night blindness reported rarely) and vitamin D deficiencies (uncommon); anaemia (frequency not known)
- Anorexia and hyperchloraemic acidosis in children and patients with renal impairment (uncommon); oedema (frequency not known)
- Intestinal obstruction (rare, reported post-marketing, including deaths in paediatric patients); rash and irritation of skin, tongue and perianal area; osteoporosis (uncommon); arthritis and backache
Interactions
- Colestyramine may bind other drugs given concurrently and impede their absorption — the interval between administration of colestyramine and other medication should be as great as is feasible, and patients should take other drugs at least one hour before or four to six hours after colestyramine (from §4.4; eMC §4.5 was NOT included in this bundle, so the itemised UK interaction list has not been verified)
- May interfere with the absorption of fat-soluble vitamins — the diet may require supplementation with vitamins A, D and K during prolonged high-dose administration
Clinical monograph
How it works
It binds bile acids in the gut to form an insoluble complex that is excreted in the faeces, interrupting enterohepatic recirculation and increasing hepatic conversion of cholesterol to bile acids.
Prescribing in practice
- It binds many other drugs in the gut and reduces their absorption, so administer other medicines well before or after it, and be aware it can impair absorption of fat-soluble vitamins on prolonged use.
- Constipation is common and it should be avoided in complete biliary obstruction, where it is ineffective.
- Prolonged use may warrant supplementation of fat-soluble vitamins, particularly in children or with high doses.
Monitoring
Monitor lipids where used for hyperlipidaemia and consider fat-soluble vitamin status with prolonged therapy.
Counselling the patient
- Mix the powder thoroughly with water or a suitable liquid before taking, as directed.
- Take your other medicines at a separate time, at least an hour before or several hours after this one.
- Tell your prescriber if you become constipated.
Evidence & guidelines
Established prescribing references support colestyramine for bile-acid diarrhoea and cholestatic pruritus, and its propensity to bind co-administered drugs is a well-recognised interaction.
Reference: NICE CG149 Jaundice in Adults; SeHCAT Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).
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