Disulfiram produces a sensitivity to alcohol which results in a highly unpleasant reaction when the patient under treatment ingests even small amounts of alcohol.
Disulfiram blocks the oxidation of alcohol at the acetaldehyde stage. During alcohol metabolism following disulfiram intake, the concentration of acetaldehyde occurring in the blood may be 5 to 10 times higher than that found during metabolism of the same amount of alcohol alone.
Accumulation of acetaldehyde in the blood produces a complex of highly unpleasant symptoms referred to hereinafter as the disulfiram-alcohol reaction. This reaction, which is proportional to the dosage of both disulfiram and alcohol, will persist as long as alcohol is being metabolized. Disulfiram does not appear to influence the rate of alcohol elimination from the body.
Disulfiram is absorbed slowly from the gastrointestinal tract and is eliminated slowly from the body. One (or even two) weeks after a patient has taken his last dose of disulfiram, ingestion of alcohol may produce unpleasant symptoms.
Prolonged administration of disulfiram does not produce tolerance; the longer a patient remains on therapy, the more exquisitely sensitive he becomes to alcohol.