Disulfiram, better known as Antabuse, is a common drug for the treatment of alcoholism. The detoxification of ethanol is a two-step process. Ethanol is oxidized to acetaldehyde by the alcohol dehydrogenase, and acetaldehyde is oxidized to acetic acid by aldehyde dehydrogenase (LADH). The second step is slower than the first step, so excessive drinking causes an accumulation of acetaldhyde, a toxic substance responsible for the common hangover.
Sulfiram is a potent inhibitor of LADH. Drinking alcohol after taking the drug produces a large amount of acetaldehyde very rapidly, resulting nausea, headache and all the other common symptoms of a severe hangover.