Colestyramine

How it works

It binds bile acids in the intestinal lumen 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 can interfere with the absorption of fat-soluble vitamins and many oral drugs, so other medicines should be taken well before or after the resin to avoid binding.
• It is contraindicated in complete biliary obstruction, where bile acid secretion into the gut is absent.
• Constipation is common and prolonged use may aggravate fat malabsorption; consider supplementing fat-soluble vitamins where treatment is prolonged.

Monitoring

Monitor the lipid profile when used for hypercholesterolaemia and review symptom control, bowel habit and, with prolonged use, fat-soluble vitamin status.

Counselling the patient

• Mix the powder with water or a soft food and take it well apart from your other medicines.
• Tell your doctor if you become constipated.
• Take any other tablets at least an hour before or several hours after this medicine.

Evidence & guidelines

Its lipid-lowering and bile-acid-binding effects are well established, supported by long clinical use and reflected in current prescribing references.