Urinary excretion of p-hydroxylated methamphetamine metabolites in man. II. Effect of alcohol intake on methamphetamine metabolism.

The effect of drinking alcoholic beverages on methamphetamine metabolism was investigated in man. The subjects, 97 males and 9 females, were divided into three groups by evaluation of their urinary pH; i.e., acidic, subacidic and neutral groups. The subjects in each group were further divided into ethanol-positive subjects and ethanol-negative subjects, depending on the presence or absence of ethanol in their urine. Gas chromatographic analysis showed the urinary concentrations of methamphetamine in the ethanol-positive subjects to be higher than those in the ethanol-negative subjects in both the acidic and subacidic urinary pH groups. Liquid chromatography, on the other hand, showed the urinary concentrations of p-hydroxymethamphetamine and p-hydroxyamphetamine for the ethanol-positive subjects to be lower than those for the ethanol-negative subjects in all three groups. The relative proportions of p-hydroxylated metabolites to unchanged methamphetamine in urine, therefore, were severely reduced in the ethanol-positive subjects. These results suggest that drinking alcoholic beverages probably results in a suppression of methamphetamine metabolism in man.