The pharmacokinetics of ezetimibe.

Ezetimibe is the first member of a new class of selective cholesterol absorption inhibitors. The drug and its active glucuronide metabolite impair the intestinal reabsorption of both dietary and hepatically excreted biliary cholesterol through inhibition of a membrane transporter yet to be identified. Absorption of ezetimibe is rapid and not altered by food content following oral administration. The drug is not metabolized by the cytochrome P450 system but extensive glucuronidation takes place in the intestine. Consequently, plasma concentrations of ezetimibe represent approximately 10% of total ezetimibe in plasma. Enterohepatic recirculation observed for ezetimibe and its glucuronimide significantly increases the residence time of these compounds in the intestine, at their site of action. Elimination of ezetimibe glucuronimide appears impaired in elderly patients and patients with renal insufficiency with plasma concentrations increased 1.5- to 2-fold. So far, no drug interaction study has been associated with major changes in either the pharmokinetics of ezetimibe or coadministered drugs.