indication

Chenodiol is indicated for patients with radiolucent stones in well-opacifying gallbladders, in whom selective surgery would be undertaken except for the presence of increased surgical risk due to systemic disease or age. Chenodiol will not dissolve calcified (radiopaque) or radiolucent bile pigment stones.

pharmacology

It acts by reducing levels of cholesterol in the bile, helping gallstones that are made predominantly of cholesterol to dissolve. Chenodeoxycholic acid is ineffective with stones of a high calcium or bile acid content.

mechanism of action

Chenodiol suppresses hepatic synthesis of both cholesterol and cholic acid, gradually replacing the latter and its metabolite, deoxycholic acid in an expanded bile acid pool. These actions contribute to biliary cholesterol desaturation and gradual dissolution of radiolucent cholesterol gallstones in the presence of a gall-bladder visualized by oral cholecystography. Bile acids may also bind the the bile acid receptor (FXR) which regulates the synthesis and transport of bile acids.

toxicity

Hepatotoxic.

biotransformation

Chenodiol is well absorbed from the small intestine and taken up by the liver where it is converted to its taurine and glycine conjugates and secreted in bile. At steady-state, an amount of chenodiol near the daily dose escapes to the colon and is converted by bacterial action to lithocholic acid. About 80% of the lithocholate is excreted in the feces; the remainder is absorbed and converted in the liver to its poorly absorbed sulfolithocholyl conjugates. During chenodiol therapy there is only a minor increase in biliary lithocholate, while fecal bile acids are increased three- to fourfold.

absorption

Chenodiol is well absorbed from the small intestine.

route of elimination

About 80% of its bacterial metabolite lithocholate is excreted in the feces.