A randomized trial in primary biliary cirrhosis comparing ursodeoxycholic acid in daily doses of either 10 mg/kg or 20 mg/kg. Dutch Multicentre PBC Study Group.

Background: Ursodeoxycholic acid (UDCA) prolongs transplantation-free survival in primary biliary cirrhosis (PBC). However, the optimal therapeutic dose has not been established.

Aim: To compare the effects of UDCA administered in daily doses of 10 vs. 20 mg/kg on symptoms, liver biochemistry and biliary UDCA enrichment.

Methods: A 6-month multicentre randomized open controlled trial was conducted to assess the effects of an increase in the dose of UDCA to 20 mg/kg/day vs. continuation of 10 mg/kg/day for patients who had not achieved biochemical normalization during treatment for at least 6 months with the 10 mg/kg dose. Clinical and laboratory evaluations were performed at entry and at 3-month intervals. The percentage UDCA in duodenal bile was assessed at entry and at 6 months.

Results: Sixty-one patients were enrolled. No side-effects of UDCA were observed. Within the 20 mg/kg/day group significant decreases were found for alkaline phosphatase (- 8%; P = 0.003), aspartate aminotransferase (- 11%; P = 0.01), alanine aminotransferase (- 17%; P < 0.001), gamma-glutamyl transferase (- 34%; P < 0.001), immunoglobulin M (- 11%; P = 0.002) and cholesterol (- 8.1%; P < 0.001). In the 10 mg/kg group none of these parameters differed significantly from baseline. No significant differences between dose groups for symptom scores or serum bilirubin were found. Biliary enrichment with UDCA increased from 37% to 46% in the 20 mg/kg group (P = 0.02) while remaining stable in the 10 mg/kg group.

Conclusions: Liver biochemistry improved in PBC patients receiving UDCA 20 mg/kg/day compared to a dose of 10 mg/kg/day. Both doses were equally well tolerated. These results indicate that UDCA 10 mg/kg/ day is a suboptimal dose for treating PBC.