Comparison of [ 14 C] Phenacetin and Amino[ 14 C]pyrine Breath Tests after Acute and Chronic Liver Injury in the Rat 1

Abstract

Summary

The elimination of both [¹⁴C]phenacetin and amino[¹⁴C]pyrine as judged by production of ¹⁴CO₂ in the breath showed a linear response relationship to the degree of hepatic necrosis. Further there was a differential sensitivity of the elimination of these test compounds to acute and chronic liver injury suggesting a variable susceptibility of the enzymes responsible for their metabolism. The study emphasizes the importance of using K _el rather than half-life when comparing the effect of liver injury on drug metabolism. Finally, the study demonstrates that breath tests will reflect the extent of hepatic damage and may also be used to examine the effect of liver disease on various routes of drug metabolism.