Cholestyramine
Class: anion exchange resin ; bile acid sequestrant
Indications: hypercholesterolaemia, pruritis due to partial biliary obstruction, primary biliary cirrhosis, diarrhoea associated with ileal resection or cholerrhoeic enteropathy
Contraindications: complete biliary obstruction
Cautions: diabetes, nephrotic syndrome, phenylketonuria, prolonged use, constipation Adverse reactions: common: constipation, faecal impaction, hyperchloraemic acidosis, perianal irritation, intestinal obstruction; less common: nausea, bloating, abdominal discomfort, heartburn
Metabolism/clearance: combines with bile acids and is excreted in the faeces – not absorbed
Interactions:
- decreased clinical effect/toxicity of some drugs (due to decreased absorption – see below)
- altered concentrations of some drugs that undergo enterohepatic recycling
Dosing: oral 4 to 16 g per day – initially 4 g per day; increase by 4 g at weekly intervals – give in 1 to 4 divided doses daily. Pruritis – 4 to 8 g usually sufficient
Syringe driver: not available
Mechanism of action: binds bile acids which reduces plasma bile acid concentrations
Onset: pruritus: 4 to 7 days
Notes:
- as absorption of other drugs will be affected take all other drugs 1 hour before or 4 to 6 hours after cholestyramine. Sachet contents must be mixed with 100 to 150 mL of fluid (fruit juice, skim milk, thin soup) before administering