Antipyrine kinetics in liver disease and liver transplantation.

Antipyrine kinetics were studied in seven normal subjects, 10 patients with liver disease, and 13 clinically stable patients who received a liver transplant. Five patients were studied both before and after liver transplantation. Antipyrine concentrations in saliva after oral dosing were measured by HPLC. The antipyrine t1/2 was significantly longer (P less than 0.05) in patients with liver disease than in patients undergoing liver transplantation and normal subjects. Antipyrine clearance was not significantly different between patients undergoing liver transplantation and normal subjects, but it was significantly reduced (P less than 0.05) in patients with liver disease. In five patients who were studied before and after liver transplantation, there was a significant (P less than 0.05) increase in the antipyrine clearance and a marked reduction in its t1/2 after liver transplantation. These results indicate that liver transplantation improves the drug metabolizing ability of patients with liver disease and that the oxidative metabolizing capacity of the liver in clinically stable patients after liver transplantation is similar to that of normal subjects.