The determination of aminopyrin elimination for control of the metabolic capacity of the liver in man.

The kinetics of plasma and breath elimination of aminopyrine after 14C-aminopyrine given orally were studied using an open one-compartment model and first order rates of elimination. The study comprised eight healthy volunteers and two groups with histologically verified chronic liver diseases (cirrhosis, n = 12, and chronic aggressive hepatitis, n = 12). Elimination rates from plasma and breath were significantly reduced in the group with cirrhosis, but only so in chronic aggressive hepatitis when they were expressed relative to each other. Monomethylaminopyrine was eliminated more rapidly compared to aminopyrine, and the rate of formaldehyde formation was positively correlated to the excretion rate of CO2 (r = 0.53, P less than 0.002). No correlation was found with clinical or other laboratory data in the groups of liver diseases studied. The test is a quantitative indicator of the drug metabolizing mixed function oxidases of the endoplasmatic reticulum of the liver, and may reflect the degree of damage to this system in chronic liver disease.