Disulfiram and Metronidazole Interaction
Drug interaction information between Disulfiram and Metronidazole.
Disulfiram and Metronidazole have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Disulfiram and Metronidazole. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Combining these two medicines can cause serious mental health problems, such as confusion or psychotic reactions.
What To Do
Do not take metronidazole if you have taken disulfiram within the last two weeks.
FDA Label Information
Drug Interactions Disulfiram Psychotic reactions have been reported in alcoholic patients who are using metronidazole and disulfiram concurrently. Metronidazole should not be given to patients who have taken disulfiram within the last two weeks (see CONTRAINDICATIONS ).
Disulfiram Also Interacts With
- Phenytoin moderate
- Acamprosate minor
- Amitriptyline minor
- Nabilone minor
- Naltrexone minor
Metronidazole Also Interacts With
- Theophylline major
- Lithium minor
- Cimetidine minor
- Phenytoin minor
- Phenobarbital minor
Frequently Asked Questions
Can I take Disulfiram and Metronidazole together?
This is a minor interaction. Do not take metronidazole if you have taken disulfiram within the last two weeks.
How serious is the interaction between Disulfiram and Metronidazole?
This interaction is classified as "minor" severity by the FDA. Minor interactions are unlikely to cause significant problems but should still be mentioned to your healthcare provider.
Why do Disulfiram and Metronidazole interact?
Combining these two medicines can cause serious mental health problems, such as confusion or psychotic reactions.
Understanding the Disulfiram and Metronidazole Interaction
FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Disulfiram belongs to the Aldehyde Dehydrogenase Inhibitor class and Metronidazole belongs to the Nitroimidazole Antibiotic class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Combining these two medicines can cause serious mental health problems, such as confusion or psychotic reactions. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Disulfiram has 8 total documented interactions on file in this dataset, and Metronidazole has 10. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Do not take metronidazole if you have taken disulfiram within the last two weeks. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Disulfiram or Metronidazole based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.