Fibrates are a class of medications primarily used to manage lipid levels in the blood. They address imbalances in fats like triglycerides and cholesterol. They are prescribed as part of an overall treatment plan, often alongside lifestyle modifications. Fibrates are distinct from other lipid-lowering agents, such as statins, due to their primary effects on specific lipid components.
What Fibrates Are and How They Work
Fibrates primarily lower triglyceride levels and increase high-density lipoprotein (HDL) cholesterol, often called good cholesterol. They achieve these effects by interacting with a specific protein inside cells called peroxisome proliferator-activated receptor alpha (PPARĪ±). Activating PPARĪ± leads to changes in the expression of genes involved in fat metabolism.
This activation reduces the liver’s production of very-low-density lipoprotein (VLDL), which transports triglycerides throughout the body. Fibrates also enhance the activity of lipoprotein lipase, an enzyme that breaks down triglycerides in the bloodstream, accelerating their removal. Additionally, fibrates increase the synthesis of apolipoproteins A-I and A-II, key components of HDL cholesterol, leading to higher levels of this beneficial cholesterol. This combined action results in a significant reduction in circulating triglycerides (often 25% to 50%) and a moderate increase in HDL cholesterol (typically 5% to 20%).
Why Fibrates Are Prescribed
Fibrates are commonly prescribed for individuals with very high triglyceride levels, a condition known as hypertriglyceridemia. Levels consistently above 500 mg/dL can increase the risk of acute pancreatitis, a serious inflammation of the pancreas, and fibrates are a primary therapy to reduce this risk. They are particularly useful when other lipid-lowering strategies, such as lifestyle changes or statin therapy, have not been sufficient to control triglyceride levels.
These medications are also considered for patients with mixed dyslipidemia, where both cholesterol and triglyceride levels are elevated. While statins primarily lower low-density lipoprotein (LDL) cholesterol, fibrates offer a distinct benefit by significantly impacting triglycerides and improving HDL cholesterol levels. Fibrates may be used in conjunction with statins for comprehensive lipid management, particularly in patients with diabetes or metabolic syndrome who have persistently high triglycerides and low HDL despite statin use.
Important Considerations When Taking Fibrates
Common side effects of fibrates include digestive upset (abdominal pain, constipation, or diarrhea), headaches, dizziness, and muscle pain or weakness. While generally mild, any persistent or severe symptoms should be reported to a healthcare provider.
More serious, less common, side effects can occur. Fibrates can affect liver function, leading to elevated liver enzymes, and may increase the risk of gallstones due to changes in bile composition. There is also a small risk of muscle damage, including a more severe condition called rhabdomyolysis, which can lead to kidney problems. The risk of muscle issues is higher when certain fibrates, particularly gemfibrozil, are taken with statins. Therefore, fenofibrate is generally preferred if a fibrate and statin combination is necessary, as it has a lower potential for interaction.
Fibrates can interact with other medications, such as blood thinners like warfarin, potentially increasing the risk of bleeding; close monitoring of clotting times is necessary if these drugs are co-administered. Fibrates are generally not suitable for individuals with severe liver or kidney disease, pre-existing gallbladder conditions, or those who are pregnant or breastfeeding. Regular monitoring through blood tests is important to assess the medication’s effectiveness and to check for potential side effects, including liver and kidney function.