Fibrates decrease triglyceride levels and raise HDL-cholesterol. They are less effective in lowering LDL-cholesterol and for this reason are used more often by people who have heart disease rather than high cholesterol.

However, in some cases, they are given in conjunction with cholesterol-lowering drugs to keep a patient’s heart healthy while lowering cholesterol to acceptable levels. Fibrates that are often prescribed to lower cholesterol include drugs such as Gemfibrozil.

Usually, Fibrates are taken in the morning and at night, about half an hour before eating. Among the most common side effects of these drugs are stomach ailments, a higher risk of gallstones, and an effect on medications being taken to thin the blood.

If you are taking medications intended to thin the blood, your doctor will want to take special precautions if you are also being prescribed fibrates.

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.

Fibrates and Diabetes

Type 2 diabetes patients, who face higher risk of cardiovascular disease, often take a combination of medications designed to lower their LDL or “bad” cholesterol and triglyceride levels while raising their HDL or “good” cholesterol because doctors long have thought that taken together, the drugs offer protection from heart attacks and improve survival.

But in a commentary in the New England Journal of Medicine, a trio of doctors who served on a recent Food and Drug Administration panel that evaluated the drugs’ effectiveness says the commonly prescribed medications have not been proven successful at preventing heart attacks in Type 2 diabetes patients with elevated cholesterol.

Annual sales in the U.S. for the three fibrates now approved by the FDA — gemfibrozil (Lopid), fenofibrate (Tricor) and fenofibric acid (Trilipix) — amount to billions of dollars.

“There have been few studies regarding the clinical outcome efficacy of fibrates,”

said Sanjay Kaul, MD, a commentary author and director of the Cardiology Fellowship Training Program at the Cedars-Sinai Heart Institute.

“Thousands and thousands of Americans take fibrates every day but so far, there are no long-term studies showing that fibrates lower cardiovascular risk or improve survival among diabetes patients who are also on statins.”