Lipid-lowering drugs. An overview of indications and optimum therapeutic use

Drug treatment of patients with hyperlipoproteinaemia is indicated to reduce the risk of atherosclerosis in patients with increased concentrations of atherogenic lipoproteins, and to lower the plasma concentrations of triglyceride-rich lipoproteins in patients with severe hypertriglyceridaemia who are at risk of abdominal pain and pancreatitis. Such therapy should be initiated only after satisfactory exclusion of secondary causes of hyperlipoproteinaemia, and should be regarded as an adjunct to rather than a substitute for appropriate dietary therapy. Drug therapy should be strongly considered in those patients with concentrations of atherogenic lipoproteins which exceed the 90th to 95th percentile for age. In patients with increased plasma concentrations of low density lipoproteins (LDL), agents which enhance the rate of LDL catabolism (cholestyramine and colestipol) or reduce the rate of LDL synthesis [e.g. nicotinic acid (niacin)] are the 'drugs of choice'. For those patients with concurrent hypertriglyceridaemia, nicotinic acid is the preferred initial drug, and in both patient groups combined drug therapy is often necessary to attain optimal reductions in LDL cholesterol concentrations. Clofibrate remains the 'drug of choice' for the rare patient with type III hyperlipoproteinaemia, whereas the newer agent gemfibrozil should be used in patients with plasma triglyceride concentrations above 1000 mg/dl who are at increased risk of abdominal pain and pancreatitis. Although currently limited to investigational use, mevinolin and related compounds, which are specific inhibitors of the rate-limiting enzyme in cholesterol biosynthesis (HMG Co-A reductase), offer considerable promise in the therapy of patients with primary hypercholesterolaemia due to elevated levels of LDL cholesterol.