Diabetes and Lipid Clinic of Alaska

 

 


About fibrates

Fibrates (or fibric acid derivatives) are a type of1 cholesterol-reducing drug. These medications lower the levels of fats (lipids) in the blood, including cholesterol and triglycerides. Fibrates mainly acts to lower triglycerides by reducing their production and increasing the rate at which existing triglycerides are removed from the bloodstream. Fibrates have been shown to reduce triglycerides by 35 to 50 percent in patients who have elevated triglyceride levels (hypertriglyceridemia).

In addition to lowering triglycerides, fibrates can also modestly increase HDL (“good”) cholesterol levels in most patients. They are less effective at reducing LDL (“bad”) cholesterol levels. There are three types of fibrates currently available in the United States:

  • Gemfibrozil (brand name Lopid). Has been shown to increase HDL levels by 11 percent. It is the most commonly prescribed fibrate in the United States.
  • Fenofibrate (brand names Lifibra, Tricor)
  • Fenofibric acid (Trilipix) This is FDA approved  to be used in combination with statins because of a reduced risk of negative drug interactions.

Potential side effects of fibrates

There are a number of side effects that could occur as a result of taking fibrates. Patients should notify their physician immediately if they experience any side effects such as the following:

  • Allergic reaction (sneezing, respiratory congestion, itching or skin rashes)
  • Muscle aches and pains
  • Abdominal pain (severe), especially if with nausea and/or vomiting
  • Shortness of breath or trouble breathing (fenofibrate or clofibrate)
  • Skin rash and/or hives (fenofibrate)
  • Sore throat (fenofibrate)
  • Fever or chills (fenofibrate, gemfibrozil)
  • Chest pain (clofibrate)
  • Palpitations or abnormal heartbeat (clofibrate)
  • Blood in urine and/or decreased urination (clofibrate)
  • Swelling (edema) of feet or lower legs (clofibrate)
  • Difficult or painful urination (clofibrate, gemfibrozil)
  • Coughing or hoarseness (clofibrate, gemfibrozil)
  • Pain in the lower back or side (clofibrate, gemfibrozil)

Less serious potential side effects include:

  • Gas or belching
  • Abdominal bloating and/or pain (not severe)
  • Decreased sexual interest or ability (fenofibrate, clofibrate)
  • Constipation (fenofibrate)
  • Dizziness or lightheadedness (fenofibrate)
  • Eye irritation (fenofibrate)
  • Stuffy nose (fenofibrate)
  • Increased skin sensitivity to sunlight (fenofibrate)
  • Headache (clofibrate)
  • Increased appetite or weight gain (clofibrate)
  • Sores in mouth or on lips (clofibrate)
  • Diarrhea (clofibrate, gemfibrozil)
  • Heartburn (gemfibrozil)
  • Skin rash (gemfibrozil)

A rare, but potentially fatal, side effect of fibrates is rhabdomyolysis, or muscle toxicity. Rhabdomyolysis is a condition in which muscle cells break down, releasing their contents into the bloodstream. It most often affects the muscles in the back or lower calves, although some patients report no symptoms. Rhabdomyolysis can lead to kidney or other organ failure and death. Risk of this severe complication appears to be higher in those fibrates used in conjunction with other cholesterol-reducing drugs called statins. One fibrate, fenofibrate, appears to have a lower risk of interacting with statins and is thus the preferred fibrate for combination therapy

Patients should report any of the following symptoms of rhabdomyolysis to their physicians immediately:

  • Muscle cramps, pain, swelling, weakness, stiffness and/or tenderness
  • Fever
  • Dark urine
  • Nausea and/or vomiting
  • Malaise (a general feeling of illness or discomfort)

In addition, some research suggests that taking fibrates may increase a person’s risk of developing pancreatitis (inflammation of the pancreas), gallstones and problems following gallbladder surgery. However, they may also decrease a person’s risk of having a heart attack. Patients are encouraged to discuss the potential risks and benefits of fibrates with their physicians.

Patients should consult their physician before taking any other medication (either prescription or over-the-counter) or nutritional supplements. Of particular concern to patients taking fibrates are:

  • Other cholesterol-reducing drugs. Taking more than one cholesterol reducer at a time may worsen side effects. Statins are of particular concern when taken in conjunction with fibrates such as, gemfibrozil. This may increase the patient’s risk of developing a rare, but potentially fatal reaction called rhabdomyolysis. Fenofibrate may also worsen some side effects, but is the preferred fibrate to combine with statins. For more information on rhabdomyolysis, see Statins. 

  • Anticoagulants. Medications that inhibit blood clot formation. Use with fibrates may increase the effects of anticoagulants and therefore increase the risk of bleeding. A physician may reduce the dose of anticoagulant when prescribing a fibrate.

  • Immunosuppressants (e.g., cyclosporine). Medications used to suppress the body’s immune system that are often prescribed following an organ transplant (e.g. heart transplant) to prevent the body from rejecting the donor organ. Taking certain fibrates (fenofibrate) with immunosuppressants may increase an individual’s risk of developing or worsening kidney problems.

  • Grapefruit juice. Grapefruit juice interferes with the liver’s ability to break down (metabolize) some medications. This, in turn, can cause a toxic buildup of the medication in the blood. While the buildup is less likely if the juice is ingested four or more hours prior to the medicine, patients taking fibrates are advised to refrain from drinking grapefruit juice. Patients may also be instructed to avoid eating grapefruit

Conditions of concern with fibrates

Patients should discuss with their physician the benefits and risks of taking fibrates if they have any of the following factors:

  • Liver disease (history of disease or persistently high liver enzymes). Use of fenofibrate may lead to worsening liver problems. In addition, use of clofibrate or gemfibrozil in patients with existing liver disease may result in a buildup of this drug in the bloodstream, increasing the potential for side effects.

  • Kidney disease. This condition may lead to a buildup of fibrates in the bloodstream, increasing the potential for side effects and (in the case of fenofibrate) increasing the risk of worsening existing kidney problems.

  • Gallbladder disease or gallstones. Fibrate use may lead to a worsening of these conditions.

  • Ulcers of the stomach or intestines. Use of clofibrate may lead to a worsening of ulcers.

  • Hypothyroidism (underactive thyroid gland). Use of clofibrate may result in a worsening of muscle problems associated with this condition.

  • Increased homocysteine levels. Use of fenofibrate may raise the blood level of homocysteine, an amino acid produced as a normal byproduct of the breakdown of methionine, which is an essential (dietary) amino acid acquired mostly from eating meat and protein. High homocysteine levels have been linked to artery damage, which may increase the risk of heart attack, stroke or other cardiovascular problems. Research is ongoing to determine whether high homocysteine levels are an actual cause of those conditions, or are simply associated with them for some other reason.

  • Heart transplant. Use of fenofibrate has been shown to affect the levels of cyclosporine, which could possibly lead to transplant rejections

Lifestyle considerations with fibrates

Some fibrates (e.g., clofibrate) may result in stomach upset and should therefore be taken with food. Others should be taken before eating (e.g., gemfibrozil). Patients should carefully follow the directions for taking their medication provided by their physician and pharmacy. Those who miss a dose of this medication should take it as soon as possible, unless it is nearly time for the next dose. In that case, the missed dose should be skipped. Double doses of this medication should not be taken.

Fibrates may be less effective in people who are significantly overweight. Therefore, in addition to lifestyle changes recommended to reduce blood fat levels, patients may be placed on a weight loss program. In many cases, the lifestyle changes needed to manage blood fats will be similar to those in a weight loss program (e.g., diet, exercise, stress management).

Patients should not abruptly stop or change the dosage and timing of their medications without first consulting their physicians. It is also important that patients notify all physicians (including dentists) that they are taking fibrates before undergoing any surgical procedure.

Certain fibrates (e.g., fenofibrate) may increase an individual’s sensitivity to sunlight. Therefore, those taking these medications are encouraged to wear plenty of sunscreen (sun protection factor 15 or higher) and to take other precautions when spending time outdoors. Such measures include finding shade whenever possible, avoiding peak sunlight hours, staying covered with lightweight clothing and wearing a wide brimmed hat and sunglasses.

Most patients on medication to treat high cholesterol (hypercholesterolemia) will be taking it for the rest of their lives, provided no serious side effects occur. Patients should remember that medications may control high cholesterol, but they do not cure it. Even if all their symptoms are relieved, patients should continue to take their medication exactly as directed, eat a heart-healthy diet that is low in saturated fats and keep all scheduled follow-up appointments with their physician.

Please consult with the physicians at the Diabetes and Lipid Clinic of Alaska for further information.

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