Mechanism of Action
Ursodiol (usodeoxycholic acid) is a normal, although minor, component of human bile acids. It inhibits absorption of cholesterol in the intestine and suppresses hepatic synthesis and secretion of endogenous cholesterol. Ursodiol is a hydrophilic bile acid that solubilizes cholesterol and promotes its dispersion in aqueous fluids, reducing viscosity and improving bile flow. As a result, ursodiol reduces cholestasis, as well as prevents formation and promotes dissolution of cholesterol-containing gallstones.[1,2,3]
In patients with hepatic disease, ursodiol protects hepatocytes from the cytotoxic effects of hydrophobic bile acids by competitive inhibition of their absorption in the intestine. Administration of exogenous ursodiol increases the percentage of ursodiol in the bile acid pool from 1-2% to 60% with repeated dosing. By altering the content of the normal bile acid pool, ursodiol reduces the intrahepatic concentration of these cytoxic endogenous bile acids and prevents their accumulation in patients with cholestasis. In addition to preventing direct hepatocyte damage from mitochondrial dysfunction and free radical generation, the cytoprotective and immunosuppressive effects of ursodiol may decrease the rate of hepatocyte apoptosis and fibrosis, as well as reduce injury to bile ducts and prevent abnormal bile duct proliferation.[1,2,3]
Pediatr Pharm. 2009;15(2) © 2009 Children's Medical Center, University of Virginia
Cite this: Use of Ursodiol in Infants and Children - Medscape - Feb 01, 2009.