The metabolism of antipyrine and oxazepam has been measured in twelve healthy subjects. Antipyrine, an analgesic and antipyretic drug, is extensively metabolized by oxidation at various sites and oxazepam, a benzodiazepine, is almost exclusively metabolized by conjugation with glucuronic acid. Comparing the plasma clearance rates and the plasma half lives of the two drugs, correlation coefficients of r = 0.766 (P less than 0.01) and r = 0.966 (P less than 0.01) have been obtained. The data suggests that in man the processes of oxidation and glucuronidation are linked by a common control which regulates the metabolic rates of the two reactions.

The metabolism of antipyrine (AP) has been investigated in 15 healthy subjects by relating the saliva AP elimination rates to the urinary excretion rates of 4-hydroxyantipyrine (AP-40H), 3-hydroxymethylantipyrine (AP-CH2OH) and N-demethylantipyrine (AP-NH2). Highly significant correlation coefficients have been obtained for AP-40H (r = 0.94). AP-CH2OH (r = 0.85) and for AP-NH2 (r = 0.86). While little interindividual variation occured in the urinary concentrations of AP-4OH and AP-CH2OH, two-fold variation was found for AP-NH2. The ratios of the three metabolites were highly constant over a period of several months in some subjects but slightly variable in others indicating their control by genetic and environmental factors.