Fibric acid derivatives
Fibric acid is produced by several fungi. Two derivatives of thisacid are fenofibrate and gemfibrozil. These drugs are used to re-duce high triglyceride levels and, to a lesser extent, high LDL lev-els.
Fenofibrate and gemfibrozil are absorbed readily from the GI tract and are highly protein-bound. Fenofibrate is hy-drolyzed while gemfibrozil undergoes extensive metabo-lism in the liver. Both drugs are excreted in the urine.
Although the exact mechanism of action for these drugs isn’t known, researchers believe that fibric acid derivatives may:
· reduce cholesterol production early in its formation
· mobilize cholesterol from the tissues
· increase cholesterol excretion
· decrease synthesis and secretion of lipoproteins
· decrease synthesis of triglycerides.
Gemfibrozil produces two other effects:
· It increases high-density lipoprotein (HDL) levels in the blood (remember, this is “good” cholesterol).
· It increases the serum’s capacity to dissolve additional choles-terol.
Fibric acid drugs are used primarily to reduce triglyceride levels, especially very-low-density triglycerides, and secondarily to re-duce blood cholesterol levels. They’re typically used to treat pa-tients with types II, III, IV, and mild type V hyperlipoproteinemia.
Fibric acid drugs may displace acidic drugs, such as barbitu-rates, phenytoin, thyroid derivatives, and cardiac glycosides.
· The risk of bleeding increases when fibric acid derivatives are taken with oral anticoagulants.
· Fibric acid derivatives can lead to adverse GI effects.
· The hypoglycemic effects of repaglinide may be increased and prolonged if taken with gemfibrozil.
· Use of fibric acid derivatives and HMG-CoA reductase inhibitors may increase the risk of rhabdomyolysis.