Disulfiram is a drug used to treat chronic alcoholism by blocking the break down of acetaldehyde (a byproduct of alcohol metabolism).  The disulfiram reaction is essentially a rapid severe ‘hangover’ – including flushing, palpitations, nausea, throbbing headache and weakness which is caused by high levels of acetaldehyde.

Patients taking metronidazole, the drug of choice to treat trichomoniasis and Clostridium difficile, should be warned to avoid alcohol while on medication and 3 days following to avoid a ‘disulfiram-like’ reaction. Of note, based on animal studies, in the case of metronidazole the cause may be related to enhanced brain serotonin rather than elevated acetaldehyde.