The plasma half-life and clearance of
antipyrine was investigated in patients during the acute phase and again during the recovery phase of viral
hepatitis. Each patient served as his own control, thereby eliminating genetic factors and minimising environmental factors that cause large interindividual variations in
antipyrine elimination rates. Liver function tests,
antipyrine, half-life, plasma clearance, and the apparent volume of distribution were determined in the acute and recovery period. It was found that the appaarent volume of distribution of
antipyrine did not change in five of six patients as they recovered. Five of the six patients showed prolonged plasma half-lives and decreased plasma clearance of the
drug at the time of acute illness and these parameters reached normal values during recovery. The plasma half-life and clearance of the
drug did not correlate with biochemical indices of liver function in the recovery phase. This demonstration supports the concept that
drug metabolism is frequently impaired in
liver disease.