Gemfibrozil, or 5-(2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), is drug that lowers serum triglyceride levels, with variable effects on cholesterol. The VLDL fraction is preferentially lowered and LDL less so. The HDL subfractions HDL2 and HDL3, and apolipoproteins A-I and A-II, are increased. Gemfibrozil is a fibric acid antilipemic drug similar to clofibrate that is used to treat hyperlipoproteinemia and supplimental therapy for type IIb hypercholesterolemia. Gemfibrozil increases lipoprotein triglyceride lipolysis by increasing the activity of extrahepatic lipoprotein lipase. Chylomicrons are degraded, VLDLs are converted to LDLs, and LDLs are converted to HDL.
Gemfibrozil increases the anticoagulant effects of anisindione, dicumarol, acenocoumarol and warfarin. There is an increased risk of myopathy/rhaddomyolysis when gemfibrizol is taken with the cholesterol lowering statin drugs atorvastatin (Lipitor), cerivastatin, fluvastatin (Lescol), lovastatin, pravastatin (Pravachol), and simvastatin (Vytorin). Gemfibrizol increases the effects and toxicity of pioglitazone, rosiglitazone and repaglinide. The statin rosuvastatin (Crestor) may increase the effect of gemfibrizol, and gemfibrizol decreases the effects of ursodiol.