Background: It is common practice to warn against intake of alcohol (ethanol) when taking metronidazole because of the risk of an effect similar to disulfiram (Antabuse). In this article we investigate whether such a warning has any real basis. KNOWLEDGE BASE: The article is based on a review of relevant literature retrieved through a search in PubMed. A search was also made in the WHO's database on adverse effects.
Results: No in-vitro studies, animal models, reports of adverse effects or clinical studies provide any convincing evidence of a disulfiram-like interaction between ethanol and metronidazole.
Interpretation: The warning against simultaneous use of alcohol and metronidazole appear to be based on laboratory experiments and individual case histories in which the reported reactions are equally likely to have been caused by ethanol alone or by adverse effects of metronidazole. Recent research does not confirm a clinically relevant interaction between ethanol and metronidazole.