Influence of rifamycin SV on bile acid metabolism in rats.

Sodium cholate was infused with or without Rifamycin SV in rats in order to determine the site of interference of the drug on hepatic bile salt metabolism. Both compounds were administered at rates such as to saturate their respective maximal excretory capacities. When Rifamycin SV was given, bile acid uptake and excretion significantly decreased, with a significant reduction of the percent of conjugated bile salts in bile. Rifamycin SV neither modified bile flow nor affected the correlation between bile flow and bile salt excretion. These data suggest that the antibiotic interferes with the three main steps of hepatic bile acid metabolism. The cholestatic effect and the modification of biliary bile salt output produced by Ryfamycin SV in rats, could be of clinical relevance.