CriticalDrug for alcohol use disorder, aldehyde dehydrogenase inhibitor×Imidazole derivatives (antiprotozoal / antibacterial)
Updated · Methodology
Mechanism
The disulfiram label attributes the interaction to a possible synergistic effect of the two drugs that causes an acute psychotic reaction and confusion. Psychotic reactions have been reported in patients with alcohol dependence who took metronidazole together with disulfiram.
Symptoms
Confusion and acute psychotic reactions in a patient who takes disulfiram or has recently taken it.
Management
The combination is contraindicated in the disulfiram label and in the US Food and Drug Administration (FDA) labels for disulfiram and metronidazole. Do not start disulfiram in a patient who is taking metronidazole or has recently taken it (disulfiram label). Do not give metronidazole to a patient who has taken disulfiram within the last two weeks (metronidazole FDA label). The Spanish metronidazole label also says the combination must be avoided (metronidazole label).
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.
Summary of a multi-drug list →
Medicine list: everything you take in one place →
Sources
- AEMPS: Ficha técnica Metronidazol Normon 250 mg comprimidos EFG (2026)– AEMPS, CIMA, nº registro 62223, revisión 01/2026, sección 4.5
- FDA: Flagyl (metronidazole) capsules – Prescribing Information (2026)– FDA, DailyMed SPL, Pfizer, Precautions (Drug Interactions)
- AEMPS: Ficha técnica: Disulfiram (nº registro 12723), sección 4.3 (2019)– AEMPS, CIMA, nº registro 12723 (Antabus), revisión 01/2019, secciones 4.3 y 4.5
- FDA: Disulfiram tablets (disulfiram) prescribing information (2025)– DailyMed setid b90f8ff4-4fb3-46ab-8149-cb55f24a4044 (Alvogen), revisión 10/2025, Contraindications