The elimination kinetics of the methyl esters of diethyldithiocarbamic acid (Me-DDC) and its monothio analogue (Me-DTC) has been compared in ten alcoholic patients after a single oral dose of 400 mg disulfiram (Antabuse). Erythrocyte aldehyde dehydrogenase (ALDH) activity was continuously followed in the subjects until complete inactivation. The relation between individual steady-state concentrations of Me-DTC in plasma, blood acetaldehyde concentration and the dose of disulfiram sufficient to give the disulfiram alcohol reaction was investigated in 12 healthy volunteers treated with increasing doses of disulfiram and then challenged with ethanol. The mean peak plasma concentration of Me-DDC occurred at 1.8 h and its plasma half-life was 6.3 h. The corresponding values for Me-DTC were 3.3 h and 11.2 h, respectively. This suggests oxidative formation of Me-DTC from Me-DDC. In alcoholics with a rapid decrease in erythrocyte ALDH activity (in less than 5 days), the mean peak plasma concentration of Me-DTC was 278 nmol.l-1, whereas the peak concentration was below the detection limit in subjects with a prolonged inactivation time (7-20 days). The healthy volunteers were divided into three groups of four subjects, with clinically valid disulfiram alcohol reactions at 100, 200, and 300 mg doses of disulfiram, respectively. The mean plasma concentrations of Me-DTC at steady-state were proportional to the disulfiram doses given, compared within groups at different doses, and between groups at equal and different optimal doses of the drug. The concentrations of Me-DTC were significantly increased, as compared above, whereas the blood concentrations of acetaldehyde were not significantly increased.(ABSTRACT TRUNCATED AT 250 WORDS)