Dose-effect relation of cholestryamine in children and young adults with familial hypercholesterolaemia.

Twenty children and young adults with familial hypercholesterolaemia (F.H.), on a diet low in cholesterol and high in polyunsaturated fats, were treated with cholestyramine in a metabolic unit to determine the decrease in plasma cholesterol and low-density lipoprotein (L.D.L.) cholesterol in relation to drug dosage, pretreatment concentrations of cholesterol and L.D.L. cholesterol, and body-weight. When the dose of cholestyramine was increased in thirteen patients by 1 g/day up to 16 g/day, given twice daily, cholesterol and L.D.L. cholesterol fell within the normal range in eleven subjects (average dose, 7 g/day), and the response was directly proportional (P less than less than 0-001) to the pretreatment concentrations of cholesterol (r = 0-89) and L.D.L. cholesterol (r = 0-93) but did not correlate with body-weight. Plasma total cholesterol and L.D.L. cholesterol continued to fall and concentrations reached a plateau after which additional cholestyramine had no further effect (average dose, 11 g/day). The L.D.L. cholesterol regression line successfully predicted the dose required to reduce L.D.L. cholesterol concentrations in seven other patients. There was a significant decrease in mean serum-folate in female patients. It was concluded that the minimum effective dose of cholestyramine in young patients with F.H. can be predicted from the pretreatment plasma total and L.D.L. cholesterol and may be given twice daily.