Colestyramine (Cholestyramine)

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.