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Here’s what to ask a doctor about hereditary angioedema

Drug interactions between disulfiram and Flagyl

Results for the following 2 drugs:
Flagyl (metronidazole)

Interactions between your drugs


metronidazole ↔ disulfiram

Applies to:Flagyl (metronidazole) and disulfiram

Consumer information for this interaction is not currently available.

CONTRAINDICATED: Use of a nitroimidazole in patients treated with disulfiram may result in psychotic reactions. The exact mechanism of interaction is unknown, but may involve additive effects on aldehyde dehydrogenase (ALDH) inhibition. The interaction has been reported with metronidazole. In one study, 6 of 29 hospitalized alcoholic patients who were treated with disulfiram (500 mg daily for one month, then 250 mg daily) and metronidazole (750 mg daily for one month, then 250 mg daily) developed acute psychoses or a confusional state, compared to none of the 29 patients receiving disulfiram alone. Five had paranoid delusions and three had visual and auditory hallucinations. Symptoms initially increased following withdrawal of the medications, but resolved slowly over two weeks and did not recur when disulfiram alone was restarted. No data are available for other nitroimidazoles or vaginally administered metronidazole.

MANAGEMENT: Nitroimidazole therapy should not be administered with disulfiram. Metronidazole and benznidazole are specifically contraindicated in patients who have taken disulfiram within the last two weeks according to their product labeling.


  1. "Product Information. Metrogel-Vaginal (metronidazole)." Curatek Pharmaceuticals Ltd, Elk Grove Village, IL.
  2. Knee ST, Razani J "Acute organic brain syndrome: a complication of disulfiram therapy." Am J Psychiatry 131 (1974): 1281-2
  3. Scher JM "Psychotic reaction to disulfiram." JAMA 201 (1967): 175
  4. "Product Information. Flagyl (metronidazole)." Searle, Skokie, IL.
  5. Rothstein E, Clancy DD "Toxicity of disulfiram combined with metronidazole." N Engl J Med 280 (1969): 1006-7
  6. "Product Information. Benznidazole (benznidazole)." Everett Laboratories Inc, West Orange, NJ.
View all 6 references

Drug and food interactions


metronidazole food

Applies to: Flagyl (metronidazole)

Consumer information for this interaction is not currently available.

CONTRAINDICATED: Use of alcohol or products containing alcohol during nitroimidazole therapy may result in a disulfiram-like reaction in some patients. There have been a few case reports involving metronidazole, although data overall are not convincing. The presumed mechanism is inhibition of aldehyde dehydrogenase (ALDH) by metronidazole in a manner similar to disulfiram. Following ingestion of alcohol, inhibition of ALDH results in increased concentrations of acetaldehyde, the accumulation of which can produce an unpleasant physiologic response referred to as the 'disulfiram reaction'. Symptoms include flushing, throbbing in head and neck, throbbing headache, respiratory difficulty, nausea, vomiting, sweating, thirst, chest pain, palpitation, dyspnea, hyperventilation, tachycardia, hypotension, syncope, weakness, vertigo, blurred vision, and confusion. Severe reactions may result in respiratory depression, cardiovascular collapse, arrhythmia, myocardial infarction, acute congestive heart failure, unconsciousness, convulsions, and death. However, some investigators have questioned the disulfiram-like properties of metronidazole. One study found neither elevations in blood acetaldehyde nor objective or subjective signs of a disulfiram-like reaction to ethanol in six subjects treated with metronidazole (200 mg three times a day for 5 days) compared to six subjects who received placebo.

MANAGEMENT: Because clear evidence is lacking concerning the safety of ethanol use during nitroimidazole therapy, patients should be apprised of the potential for interaction. Consumption of alcoholic beverages and products containing propylene glycol is specifically contraindicated during and for at least 3 days after completion of metronidazole and benznidazole therapy according to their product labeling.

Therapeutic duplication warnings

No therapeutic duplications were found for your selected drugs.

Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No information available.

Do not stop taking any medications without consulting your healthcare provider.

Disclaimer: Every effort has been made to ensure that the information provided by Multum is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. Multum's information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill, knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective, or appropriate for any given patient. Multum Information Services, Inc. does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. Copyright 2000-2018 Multum Information Services, Inc. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.