Exchange resins

Drugs include:

• cholestyramine and colestipol

Actions:

• sequester bile acids in the gut and so reduce their reabsorption after biliary excretion - this prevents their reabsorption and promotes hepatic conversion of cholesterol into bile acids
  • causes an up-regulation of LDL receptors to maintain cholesterol pool
• reduces cholesterol and LDL concentrations
• may increase plasma triglyceride concentration by increasing VLDL - this is particularly the case where triglyceride levels are already raised when exchange resin therapy can result in a substantial increase in plasma triglycerides
• note that exchange resins may decrease folate levels and folate supplementation should be considered in some groups (e.g children, pregnancy)

Contraindications:

• complete biliary obstruction

Side effects include:

• bloating, constipation, heartburn

The summary of product characteristics should be consulted before prescribing either of these drugs.