After oral administration, approximately 90% of an ursodiol dose is absorbed in the proximal jejunum and the ileum by passive diffusion. After absorption, it is extracted from the portal vein circulation by the liver. Ursodiol is then conjugated with glycine or taurine and secreted into the bile. Initially concentrated in the gallbladder, conjugated ursodiol passes into the duodenum via the cystic and common ducts. Only small amounts of ursodiol are present in the systemic circulation.[1,2,3]
Ursodiol undergoes extensive enterohepatic recirculation and may be oxidized or reduced by bacteria in the gut, producing 7-keto-lithocholic acid and lithocholic acid. These metabolic byproducts are eliminated in the feces. Urinary excretion accounts for only 1% of an oral dose. The elimination half-life of ursodiol in adults is approximately 3 to 6 days. Steady state concentrations are typically reached within 3 weeks of starting therapy. Within a week after discontinuation of therapy, ursodiol concentrations in the bile will have declined to approximately 5 to 10% of the average concentration at steady state.[1,2,3,4]
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.