The cholesterol-lowering drugs called fibrates are primarily effective in lowering triglycerides and, to a lesser extent, in increasing HDL-cholesterol levels. Gemfibrozil, the fibrate most widely used in the United States, can be very effective for patients with high triglyceride levels. However, it is not very effective for lowering LDL- cholesterol. It is used in some patients with heart disease for whom a goal of treatment is lowering triglycerides or raising HDL. One study found that patients with heart disease, somewhat elevated triglycerides, and low HDL who took fibrates had reduced risk for a heart attack. Fibrates are usually given in two daily doses 30 minutes before the morning and evening meals. The reductions in triglycerides generally are in the range of 20 to 50 percent with increases in HDL-cholesterol of 10 to 15 percent.

Fibrates are generally well tolerated by most patients. Gastrointestinal complaints are the most common side effect and fibrates appear to increase the likelihood of developing cholesterol gallstones. Fibrates can increase the effect of medications that thin the blood, and this should be monitored closely by your physician.