What Do I Need to Know About Fibrates to Lower Cholesterol?
Fibrates may lower trigylcerides 20% to 50%. They may also increase HDL - the good cholesterol - by 10% to 20%. In two large studies, both gemfibrozil and clofibrate reduced heart attack. But in a study by the World Health Organization, patients who were taking clofibrate were more likely to die from causes not related to the heart. As a result of this study, fewer doctors prescribe clofibrate. In the United States, doctors prescribe gemfibrozil more often. More recently, a third type, called fenofibrate, became available. This type may cause fewer gastrointestinal side effects.
When Are Fibrates Prescribed?
Your doctor may prescribe fibrates for you if any of these is true.- You have very high trigylcerides, are at risk for inflammation of the pancreas called pancreatitis, and do not improve with diet changes.
- You have inherited high cholesterol. You have high LDL, high triglycerides, and low HDL.
- You have diabetes and mulitple problems with the levels of fats, especially triglycerides, in your blood.
Common Names of Fibrates
The following table shows some of the most common brand and generic names for this type of medicine.
brand generic Atromid-S clofibrate Lopid gemfibrozil Tricor fenofibrate
How to Take Fibrates
Fibrates come in tablet and capsule form. Most people take gemfibrozil and clofibrate twice a day. Doctors may prescribe up to three doses of the newer fenofibrate per day.
How Fibrates Work
Fibrate medicines have three major actions. They increase the effects of enzymes that break down the fats in your blood. They reduce the amount of cholesterol and triglycerides made in your body. For the fats that your body still produces, fibrates cause your body to excrete more of them.
Precautions and Possible Side Effects of Fibrates
Researchers haven't studied the safety and effectiveness of using fibrates in children or adolescents. Precautions to take when you are on fibrates:
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Keep all your follow-up visits with your doctor to have your cholesterol checked. Fibrates lower triglycerides and increase HDL - the good cholesterol. However, they can also sometimes increase LDL - the bad cholesterol. During these visits, your doctor will also check your gallbladder and liver. Fibrates increase your risk for gallstones and for recurrence of gallbladder disease. When used with statins, fibrates may be more likely to cause liver damage as well as muscle weakness and wasting of muscle tissue, called myopathy.
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Tell your doctor about all your other health problems.
If you have heart disease, the U.S. Food and Drug Administration doesn't recommend fibrates as the only medicine you take to lower cholesterol. If you have liver or kidney problems, you shouldn't take fibrates. If you have gallbladder disease, primary biliary cirrhosis, underactive thyroid, diabetes, or peptic ulcer, you may not be able to take some forms of fibrates.
- Tell your doctor if you are pregnant or nursing. Taking fibrates in these cases may harm your developing baby.
Possible Side Effects of Fibrates. Most people can take fibrates without problems. The most common side effects are gastrointestinal complaints, such as nausea and diarrhea. Some people also develop these less common side effects:
- chest pain
- chills or fever
- decreased sex drive
- difficulty breathing
- dizziness or drowsiness
- fatigue
- headache
- impotence
- irregular heartbeat
- joint pain
- mouth sores
- muscle pain
- rash
- swelling of the tongue, lips
- swollen legs or feet
- yellowed eyes or skin caused by liver damage
In rare cases, fibrates can cause a potentially fatal disease that destroys muscle called rhabdomyolysis. If your doctor prescribes a combination of statins and fibrates, it's very important that you let your doctor know immediately if you have any unexplained muscle pain or weakness so he or she can perform a blood test for the muscle enzyme creatine kinase.
Possible Drug Interactions With Fibrates
Ask your pharmacist for a complete list of possible interactions. Tell your doctor if you take any of the following medicines before you fill a prescription for a fibrate:- the cholesterol medicines bile acid resins and statins
- blood thinners, such as warfarin
- cyclosporine, which suppresses the immune system
- diabetes medicines, including insulin and sulfonylureas
- furosemide, a diuretic
Oral contraceptives and thyroid medicine can cause your triglyceride levels to go up. So be sure to tell your doctor if you are taking either of them. If your doctor prescribes a combination of statins and fibrates, he or she will need to monitor you carefully with liver tests every 3 to 6 months. Using tobacco can decrease the effects of most meds used to treat heart disease.