Fibric acid derivatives

Fibric acid derivatives

Fibric acid is produced by several fungi. Two derivatives of this acid are fenofibrate and gemfibrozil. These drugs are used to reduce high triglyceride levels and, to a lesser extent, high LDL levels.

Pharmacokinetics

Fenofibrate and gemfibrozil are absorbed readily from the GI tract and are highly protein-bound. Fenofibrate is hydrolyzed while gemfibrozil undergoes extensive metabolism in the liver. Both drugs are excreted in the urine.

Pharmacodynamics

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.

Power in the blood

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 cholesterol.

Pharmacotherapeutics

Fibric acid drugs are used primarily to reduce triglyceride levels, especially very-low-density triglycerides, and secondarily to reduce blood cholesterol levels. They’re typically used to treat patients with types II, III, IV, and mild type V hyperlipoproteinemia.

Drug interactions

• Fibric acid drugs may displace acidic drugs, such as barbiturates, 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.