A disulfiram-like reaction has occurred in a few patients taking oral
metronidazole who drank
alcohol. There is one report of its occurrence when
metronidazole was applied as a vaginal insert, and another when
metronidazole was given intravenously. The interaction is alleged to occur with all other 5-nitroimidazoles (e.g. tinidazole).
This interaction has been extensively studied but it remains slightly controversial because the
incidence has been reported as between 0 and 100%. Because of its unpredictability all patients given
metronidazole should be warned what may happen if they drink
alcohol. The reaction, when it occurs, normally seems to be more unpleasant and possibly frightening than serious, and usually requires no treatment, although rarely fatalities have occurred.