[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Conditions](https://durgical.com/en/conditions/) › Disulfiram–ethanol reaction [Conditions](https://durgical.com/en/conditions/) · [Metabolism (biochemistry)](https://durgical.com/en/conditions/) # Disulfiram–ethanol reaction Drinking alcohol while on disulfiram makes acetaldehyde build up: flushing, nausea, palpitations and low blood pressure. Updated 2026-11-01 ## Structures involved Tap one to see what it is and open it in 3D. - [Liver](https://durgical.com/en/anatomy/liver/) - [Stomach](https://durgical.com/en/anatomy/stomach/) - [Sinoatrial (SA) node](https://durgical.com/en/anatomy/sinuatrial-node/) - [Left ventricle](https://durgical.com/en/anatomy/left-ventricle/) ## In biochemistry - [Ethanol metabolism: Step 2 · Mitochondrial aldehyde dehydrogenase (ALDH2)](https://durgical.com/en/biochemistry/pathways/ethanol-metabolism/#paso-2) - [Aldehyde dehydrogenase 2 (ALDH2)](https://durgical.com/en/biochemistry/enzymes/aldehyde-dehydrogenase-2/) - [Acetaldehyde](https://durgical.com/en/biochemistry/molecules/acetaldehyde/) ## Why it happens - [Alcohol: how it injures the liver, brain, heart and fetus](https://durgical.com/en/general-pathology/alcohol-how-it-injures-the-liver-brain-heart-and-fetus/) ## What it is A toxic reaction that appears when alcohol is drunk while aldehyde dehydrogenase is inhibited by disulfiram (or, similarly, by other drugs or the ALDH2*2 variant). ## Who gets it It occurs in people treated with disulfiram for alcohol dependence who drink or are exposed to hidden alcohol (syrups, mouthwashes, perfumes, vinegars, sauces). A similar reaction, alcohol flushing, is common in East Asian people with ALDH2*2. ## Causes - Alcohol during disulfiram treatment or up to about two weeks after stopping it - Hidden alcohol in medicines, food or cosmetics - Disulfiram-like reactions described with metronidazole, some cephalosporins, griseofulvin and the mushroom Coprinopsis atramentaria ## Risk factors - Disulfiram treatment without enough information - Pre-existing cardiovascular disease - Drinking a large amount of alcohol ## Pathophysiology Disulfiram and its metabolites (such as methylated diethylthiocarbamate) modify ALDH2's catalytic cysteine and inactivate it irreversibly; activity returns only when the [liver](https://durgical.com/en/anatomy/liver/) makes new enzyme. On drinking, alcohol dehydrogenase keeps making acetaldehyde, which is not oxidised and rises several-fold in the blood. Acetaldehyde releases histamine and dilates vessels (flushing, throbbing headache, hypotension), triggers vomiting and causes reflex tachycardia. Disulfiram also inhibits dopamine β-hydroxylase: less noradrenaline, which worsens the hypotension. ## Symptoms and signs - Flushing of face and neck minutes after drinking - Throbbing headache - Intense nausea and vomiting - Palpitations and tachycardia - Sweating, breathlessness and dizziness - Blurred vision and confusion ## Red flags - Severe hypotension or shock - [Chest](https://durgical.com/en/anatomy/region/chest/) pain or arrhythmias - Seizures or loss of consciousness ## Diagnosis **Clinical** Clinical diagnosis: typical symptoms soon after drinking in someone taking disulfiram or another implicated drug. **Tests** Electrocardiogram, electrolytes and glucose in moderate or severe cases; ethanol level when in doubt. **Imaging** Imaging is not usually needed. ## Treatment **Acute** Supportive measures: lying flat, intravenous fluids and blood pressure control. **Medical** Antiemetics and, in severe cases, vasopressors; fomepizole has been used in severe cases to slow acetaldehyde formation. **Follow-up** Cardiac monitoring until symptoms settle, usually within a few hours. **Conservative** Informing people who receive disulfiram about hidden alcohol sources. ## Complications - Shock - Arrhythmias, myocardial ischaemia - Bronchospasm - Death (rare) ## Prognosis Most reactions settle within hours with support; severe ones occur with large amounts of alcohol or pre-existing heart disease. ## Prevention - Explaining the reaction before starting disulfiram and reviewing hidden alcohol sources - Avoiding alcohol during and after treatment with implicated drugs ## Test yourself Think of the answer, then tap the question to see it. ## Which enzyme does disulfiram inhibit and what builds up? Aldehyde dehydrogenase (ALDH2); acetaldehyde builds up. ## Why can the reaction occur days after stopping disulfiram? The inhibition is irreversible: the liver must make new enzyme. ## Why is hypotension intense in this reaction? Acetaldehyde dilates vessels and disulfiram inhibits dopamine β-hydroxylase, so there is less noradrenaline. ## Which genetic variant causes a similar flush with alcohol? ALDH2*2, common in East Asia. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/conditions/disulfiram-ethanol-reaction/) ## Related conditions - [Alcoholic liver disease (biochemistry)](https://durgical.com/en/conditions/alcoholic-liver-disease/) Educational information, not medical advice. For any symptom, see a health professional. Sources: [Disulfiram: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682602.html) (MedlinePlus, US National Library of Medicine, 2026); [Alcohol use disorder: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/alcohol-use-disorder/) (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011). [← All conditions](https://durgical.com/en/conditions/) ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/conditions/disulfiram-ethanol-reaction/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/disulfiram-ethanol-reaction/