The effectual level of ursodeoxycholic acid in therapy for non-advanced chronic cholestasis is fifty percent of total serum bile acids

Ursodeoxycholic acid therapy (600 mg/day) was evaluated in twelve patients with nonadvanced chronic cholestasis. Within four months, ursodeoxycholic acid replaced more than 50% of total bile acids in 8 patients and the reduction of serum γ-glutamyltranspeptidase, alkaline phosphatase and transaminases averaged 30% or more. The serum levels of chenodeoxycholic acid depend on those of ursodeoxycholic acid, but are not related to those of biochemical parameters. Drug therapy was continued in three poor responders for 2–3 four-month periods. In one case an increase of the serum proportion of ursodeoxycholic acid was associated with a reduction in biochemical parameters. The other two cases had high serum levels of chenodeoxycholic acid and/or cholic acid throughout the entire course of treatment. While the treatment of chronic cholestasis requires an effectual serum proportion of ursodeoxycholic acid, it is important to distinguish endogenous persistent hyper-bile-acidemia from ursodeoxycholic acid-related acidemia.