Gemfibrozil belongs to the class of medications known as fibrates. It is used to treat high cholesterol. It works by blocking the production of certain types of cholesterol, especially the type known as triglycerides. Gemfibrozil is used in combination with a healthy diet and exercise to lower cholesterol levels in the blood. Reduction of cholesterol levels has been shown to reduce the risks associated with heart disease, such as heart attack.
Gemfibrozil is a fibric acid antilipemic agent similar to clofibrate. Gemfibrozil possesses biologic actions distinct from those of clofibrate. Gemfibrozil effectively lowers serum triglycerides and also produces favorable changes in lipoproteins, but the HMG-CoA reductase inhibitors are more effective in hyperlipoproteinemia.
Gemfibrozil has been shown to inhibit peripheral lipolysis and to decrease hepatic extraction of free fatty acids, which, in turn, decreases hepatic triglyceride production. Gemfibrozil also inhibits the synthesis and increases the clearance of apolipoprotein B, a carrier molecule for VLDL. Gemfibrozil may also accelerate turnover and removal of cholesterol from the liver and increase excretion of cholesterol into the feces. Gemfibrozil's effects on triglyceride concentrations and HDL fraction have been shown to be greater than those of clofibrate, to which it is structurally related. Gemfibrozil has variable effects on LDL cholesterol. Although it causes moderate reductions in patients with type IIa hyperlipoproteinemia, changes in patients with either type IIb or type IV hyperlipoproteinemia are unpredictable. In general, the HMG-CoA reductase inhibitors are more effective than gemfibrozil in reducing LDL cholesterol.