Fibrates, also known as fibric acid derivatives, are a class of medications primarily used to treat lipid disorders. They are particularly effective in lowering triglyceride levels and, to a lesser extent, in increasing high-density lipoprotein cholesterol (HDL-C, often referred to as "good" cholesterol). The impact of fibrates on low-density lipoprotein cholesterol (LDL-C, or "bad" cholesterol) is variable and less pronounced.
Mechanism of Action: Fibrates work by activating peroxisome proliferator-activated receptors (PPARs), specifically PPAR-alpha. This activation leads to several metabolic effects:
- Increase in the oxidation of fatty acids in liver and muscle.
- Decrease in the production of triglycerides in the liver.
- Increase in the removal of triglycerides from the blood.
- Increase in the production of HDL-C.
Commonly Used Fibrates:
- Fenofibrate: Used to treat high levels of triglycerides and often prescribed when dietary changes alone have been insufficient.
- Gemfibrozil: Another commonly prescribed fibrate, particularly effective in lowering triglycerides and raising HDL-C levels.
Indications:
- Primarily indicated for hypertriglyceridemia, especially in cases where triglyceride levels are very high and pose a risk for pancreatitis.
- Sometimes used for mixed hyperlipidemia (high triglycerides and low HDL-C) when statins are not suitable or in addition to statins for additive effects.
Side Effects:
- Gastrointestinal discomfort, such as nausea and diarrhea.
- Increased risk of developing gallstones.
- Potential for muscle-related symptoms, especially when used in combination with statins.
- Changes in liver enzyme levels, requiring monitoring.
Contraindications:
- Liver disease, including primary biliary cirrhosis.
- Severe kidney disease.
- Pre-existing gallbladder disease.
Drug Interactions:
- Increased risk of muscle toxicity when used with statins.
- Interactions with anticoagulants (like warfarin) as fibrates can enhance the effects of anticoagulants.
Clinical Considerations:
- Regular monitoring of lipid levels, liver function tests, and kidney function is recommended.
- Fibrates should be used as part of a comprehensive approach to lipid management, including diet, exercise, and other lifestyle modifications.
In summary, fibrates are a valuable tool in managing certain lipid disorders, particularly high triglycerides. Their use should be individualized based on the patient's lipid profile, tolerance, and the presence of other medical conditions.