What does a fibrate (fibrates are a class of medications) do?

What Fibrates Do

Fibrates are a class of medications that primarily reduce triglyceride levels, modestly increase HDL cholesterol, and can reduce risk for coronary heart disease events in patients with high triglycerides and low HDL-C, especially in those with diabetes or metabolic syndrome. 1, 2

Primary Mechanisms and Effects

• Fibrates act as peroxisome proliferator-activated receptor-alpha (PPAR-α) agonists, modifying lipid metabolism 3
• They significantly decrease serum triglycerides by 20-50% 4, 3
• They modestly increase HDL cholesterol levels by up to 30% 4, 5
• They have variable effects on LDL cholesterol, with some fibrates being effective in lowering LDL-C 6, 5
• They can change the distribution of LDL toward larger, less atherogenic particles 5

Clinical Applications

• Fibrates are primarily used for patients with hypertriglyceridemia, mixed hyperlipidemia, and diabetic dyslipidemia 5
• They are particularly beneficial in patients with:
  • High triglycerides (>200 mg/dL) 2
  • Low HDL cholesterol 2
  • Features of metabolic syndrome or diabetes 2, 7
• They may be used as monotherapy or in combination with statins for patients not reaching lipid goals with statins alone 6

Cardiovascular Benefits

• Post-hoc analyses of clinical trials indicate fibrates reduce risk for CHD events in patients with high triglycerides and low HDL-C 2
• The FIELD trial showed a significant 11% reduction in total cardiovascular disease events with fenofibrate 8
• In the ACCORD Lipid trial, fenofibrate plus statin showed a non-significant 8% relative risk reduction in major adverse cardiovascular events compared to statin monotherapy 8
• Subgroup analyses suggest greater benefit in patients with both high triglycerides (>204 mg/dL) and low HDL cholesterol (<34 mg/dL) 4

Microvascular Benefits

• Recent evidence shows efficacy of fenofibrate in reducing microvascular complications in diabetic patients, including: 9
  • Progression of diabetic retinopathy
  • Progression of microalbuminuria and nephropathy
  • Development of sensory neuropathy
  • Risk of leg amputation

Available Fibrates

• Common fibrates include fenofibrate, gemfibrozil, bezafibrate, etiofibrate, and ciprofibrate 9
• Fenofibrate appears to have a better safety profile than gemfibrozil when combined with statins 9, 10

Safety Considerations

• Fibrates are generally well-tolerated but have several potential safety issues: 10
  • May cause reversible increases in serum creatinine and homocysteine levels
  • Associated with slight risk (<1%) for myopathy, cholelithiasis, and venous thrombosis
  • Can cause gastrointestinal symptoms and elevated liver function tests 11
• When combined with statins:
  • Fenofibrate is preferred over gemfibrozil due to lower risk of myopathy 2, 10
  • Gemfibrozil interferes with statin metabolism and increases risk of myopathy 12

Clinical Trial Evidence

• The evidence base for fibrate therapy is not as strong as that for statins 2
• Major trials include:
  • Helsinki Heart Study - showed benefit in primary prevention 8
  • FIELD (Fenofibrate Intervention and Event Lowering in Diabetes) - showed reduction in total cardiovascular events 8
  • ACCORD Lipid - showed potential benefit in specific subgroups with dyslipidemia 8

Practical Considerations

• Fibrates may be particularly useful as adjunctive therapy for patients with residual dyslipidemia despite statin therapy 9
• They should be used with caution in patients with renal impairment 10
• Clinicians should measure serum creatinine before starting fibrate therapy and adjust dosing accordingly 10