[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Medicines for alcohol use disorder](https://durgical.com/en/pharmacology/classes/medicines-for-alcohol-use-disorder/) › Disulfiram

[Pharmacology](https://durgical.com/en/pharmacology/) · [Medicines for alcohol use disorder](https://durgical.com/en/pharmacology/classes/medicines-for-alcohol-use-disorder/)

# Disulfiram

A medicine that makes drinking alcohol very unpleasant by blocking acetaldehyde breakdown. It is never given without the person's full knowledge.

Updated 2026-11-01

- Class: [Medicines for alcohol use disorder](https://durgical.com/en/pharmacology/classes/medicines-for-alcohol-use-disorder/)
- Enzyme: Aldehyde dehydrogenase (ALDH2)
- ATC code: N07BB01

## Mechanism of action

Ethanol is turned into acetaldehyde and then into acetate by aldehyde dehydrogenase. Disulfiram, through its active metabolites, irreversibly inactivates this enzyme, so even a little alcohol makes acetaldehyde build up in the blood and causes a sudden, unpleasant and sometimes dangerous reaction.

- Ethanol is oxidised to acetaldehyde
- Disulfiram metabolites block aldehyde dehydrogenase
- Acetaldehyde builds up in the blood
- Flushing, headache, vomiting and low blood pressure

## Pharmacokinetics

**Metabolism**
Converted to active metabolites that inactivate the enzyme

**Half-life**
The enzyme block lasts: a reaction is possible up to 14 days after the last dose

**Onset and duration**
Started only after at least 12 hours without alcohol

## Indications

- Aid in selected people with chronic alcohol use disorder who want to stay sober, with supportive and psychological treatment [Alcohol use disorder →](https://durgical.com/en/conditions/alcohol-use-disorder/)

## Adverse effects

### Common

- Mild drowsiness and tiredness in the first weeks
- Metallic or garlic-like aftertaste
- Headache, impotence and skin eruptions

### Serious (rare, important)

- Disulfiram–alcohol reaction: flushing, throbbing headache, vomiting, fast heartbeat, hypotension, fainting; in severe cases respiratory depression, cardiovascular collapse or death
- Hepatitis, including fulminant liver failure
- Optic and peripheral neuritis
- Psychotic reactions

## Contraindications

- Alcohol intoxication, or giving it without the person's full knowledge
- Recent or current metronidazole, paraldehyde, alcohol or alcohol-containing products (such as cough syrups)
- Severe heart muscle disease or coronary occlusion
- Psychoses
- Hypersensitivity to disulfiram or thiuram compounds (rubber)

## Key interactions

**Alcohol in any form (sauces, vinegars, cough mixtures, aftershave, rubbing lotions)**
Disulfiram–alcohol reaction

**Metronidazole**
Contraindicated

**Phenytoin**
Phenytoin toxicity; levels are checked

**Oral anticoagulants**
Longer prothrombin time; the dose may need adjustment

**Isoniazid**
Unsteady gait or mental changes

## What is monitored

- Liver tests at baseline and about 10 to 14 days later, then periodically
- Blood counts and chemistry
- Phenytoin levels or prothrombin time if those drugs are used

## Administration and safety

- Given by mouth, only with the person's full knowledge and consent
- Never started in someone intoxicated; at least 12 hours alcohol-free first
- Relatives are told it must never be given secretly

## Nursing care

- Confirm at least 12 hours without alcohol before the first dose
- Teach to avoid hidden alcohol: sauces, vinegars, cough syrups, aftershave, rubbing lotions
- Teach that a reaction is possible up to 14 days after the last dose
- Teach to report yellow skin, dark urine or tiredness (hepatitis)
- Suggest carrying a card that states disulfiram use, the reaction symptoms and whom to call

## Pregnancy and breastfeeding

Safety in pregnancy is not established; it is used only when the likely benefit outweighs the possible risk.

## Memory aid

Disulfiram: «DIS-gust-iram» – blocks ALDH, acetaldehyde floods in, 14 days of risk; never secretly.

## Test yourself

Think of the answer, then tap the question to see it.

## Why does alcohol cause flushing and vomiting in someone on disulfiram?

Aldehyde dehydrogenase is blocked, so acetaldehyde builds up in the blood.

## For how long after the last dose can a disulfiram–alcohol reaction occur?

Up to 14 days.

## Which antibiotic is contraindicated with disulfiram?

Metronidazole.

## Which organ is monitored with blood tests during disulfiram treatment?

The liver, because of the risk of hepatitis and liver failure.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/disulfiram/)

## Related drugs

- [Acamprosate](https://durgical.com/en/pharmacology/acamprosate/)
- [Naltrexone](https://durgical.com/en/pharmacology/naltrexone/)
- [Phenytoin](https://durgical.com/en/pharmacology/phenytoin/)

## Related conditions

- [Alcohol use disorder](https://durgical.com/en/conditions/alcohol-use-disorder/)

[← Back to the class: Medicines for alcohol use disorder](https://durgical.com/en/pharmacology/classes/medicines-for-alcohol-use-disorder/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - DISULFIRAM tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b90f8ff4-4fb3-46ab-8149-cb55f24a4044) (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 27 (McGraw Hill, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N07BB01) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/disulfiram/