The aminopyrine breath test for the evaluation of liver function in alcoholic patients: drug pharmacokinetics and environmental factors.

Drug pharmacokinetics and environmental factors contribute to the selection of an ideal drug substrate for the determination of liver function via the carbon dioxide breath test. An ideal drug should be rapidly absorbed, and have an hepatic extraction ratio between 0.2 and 0.5. Its metabolism should not be induced by ethanol or be affected by cigarette smoking. The relative promise of caffeine and methacetin are compared to aminopyrine.