Ursodeoxycholic acid

Ursodeoxycholic acid is a hydrophilic bile acid used to dissolve selected cholesterol gallstones and treat primary biliary cholangitis. It reduces cholesterol saturation in bile and can protect bile-duct cells.

Enterohepatic circulation: The recycling of compounds between the liver, bile, intestine, and portal blood. Recycling keeps administered ursodeoxycholic acid in the bile-acid pool.
Primary biliary cholangitis: A chronic autoimmune disease that damages small bile ducts within the liver. Ursodeoxycholic acid is standard first-line therapy for this disease.
Chenodeoxycholic acid: A primary bile acid synthesized by the liver from cholesterol. It is more hydrophobic than ursodeoxycholic acid and can serve as a contrast in bile-acid therapy.
Bear bile: Bile collected from bears, historically used in several East Asian medical traditions. Ursodeoxycholic acid was isolated from bear bile, giving the compound its name.
Cholesterol gallstone: A gallbladder stone composed mainly of crystallized cholesterol. The drug can dissolve these stones by lowering cholesterol saturation in bile.
Gallstone disease: Conditions caused by stones forming in the gallbladder or biliary tract. The medicine offers a nonsurgical option for selected cholesterol stones.
Bile: A digestive fluid produced by the liver and stored in the gallbladder. Ursodeoxycholic acid acts within bile and changes its composition.
Japanese pharmacognosy: The study of medicinal substances obtained from natural sources in Japan. Research on bear bile helped identify and characterize ursodeoxycholic acid.
Cholesterol saturation index: A measure comparing the cholesterol in bile with the amount it can keep dissolved. Ursodeoxycholic acid lowers this index, making cholesterol less likely to precipitate.
Cholelithiasis: The presence of gallstones in the gallbladder. Stone composition and gallbladder function determine whether drug dissolution is suitable.

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GallstoneRelated: It offers nonsurgical dissolution for some small, noncalcified cholesterol stones.