Can You Take Metronidazole with Alcohol?
Last reviewed: · Source: US FDA drug label database
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Never drink alcohol with metronidazole — the combination causes a severe disulfiram-like reaction with vomiting, flushing, rapid heart rate, and severe distress.
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Is it safe to take Metronidazole with Alcohol?
Metronidazole and alcohol have one of the most well-known dangerous drug-alcohol interactions. Combining them causes a disulfiram-like reaction (similar to the drug Antabuse) characterised by intense flushing, severe nausea and vomiting, headache, rapid heart rate, and a profound feeling of illness. This is not just unpleasant — it can be dangerous, particularly in people with heart conditions. You must completely avoid alcohol during your course of metronidazole and for at least 48 hours after the last dose.
How do Metronidazole and Alcohol interact?
Metronidazole inhibits aldehyde dehydrogenase (ALDH2), the enzyme responsible for converting acetaldehyde to acetic acid in alcohol metabolism. When alcohol is ingested with metronidazole, acetaldehyde accumulates in the bloodstream to toxic levels, causing the disulfiram-like reaction. This interaction also applies to alcohol-containing mouthwashes, some cough syrups, and topical alcohol preparations.
Data sourced from the US Food and Drug Administration (FDA) drug label database: FDA metronidazole drug label — disulfiram-like reaction with alcohol; OpenFDA drug label data.
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Everyone taking metronidazole or tinidazole. Also be aware of hidden alcohol in medications, mouthwashes, and cooking sauces. This reaction applies even to small amounts of alcohol.
What if I've already taken Metronidazole and Alcohol?
If you have taken metronidazole and drunk alcohol and feel very unwell (flushing, vomiting, rapid heart rate, dizziness), rest quietly. Drink water. If symptoms are severe or you have a heart condition, call 999 or go to A&E.
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Not sure if this combination is safe for your specific situation?
HealthLabs.com lets you check liver enzyme or kidney function levels before combining medications long-term — no GP referral needed.
Check your levels at HealthLabs →Always speak to your pharmacist or GP for personalised medical advice. Affiliate link — we may earn a commission.
Frequently Asked Questions
Can you drink alcohol with metronidazole?
No — alcohol must be completely avoided while taking metronidazole and for 48 hours after the last dose. Metronidazole causes a severe disulfiram-like reaction with alcohol: intense nausea, vomiting, flushing, rapid heart rate, and headache. This is not just feeling unwell — it is a genuine toxic reaction.
Why can't you drink on metronidazole?
Metronidazole inhibits the enzyme acetaldehyde dehydrogenase, which breaks down alcohol in the body. Alcohol accumulates as toxic acetaldehyde, causing flushing, vomiting, rapid heart rate, and severe headache. This is the same reaction caused deliberately by disulfiram (Antabuse) — a drug used to treat alcohol dependence.
What happens if you drink alcohol while taking metronidazole?
Within 15-30 minutes of drinking on metronidazole: intense flushing, severe nausea and vomiting, rapid heart rate (tachycardia), throbbing headache, and low blood pressure. In severe cases, chest pain and difficulty breathing. The reaction can last several hours. Medical attention is needed if the reaction is severe.
How long after metronidazole can I drink alcohol?
Wait at least 48 hours after your last metronidazole dose before drinking any alcohol. Some sources advise 72 hours to be safe. Metronidazole's half-life is 6-8 hours, but its inhibitory effect on acetaldehyde dehydrogenase can persist longer than the drug itself stays in your system.
Can I drink alcohol 24 hours before taking metronidazole?
Avoid alcohol for 24-48 hours before starting metronidazole if possible. While the worst reactions occur when alcohol is in your system during metronidazole treatment, it's best to be fully alcohol-free before starting the course.
Metronidazole and alcohol — the disulfiram reaction explained
The disulfiram-like reaction occurs because metronidazole inhibits acetaldehyde dehydrogenase (ALDH2), the enzyme responsible for the second step of alcohol metabolism. Ethanol is converted to acetaldehyde normally, but acetaldehyde cannot be further converted — it accumulates to toxic levels. Acetaldehyde is what causes all the unpleasant symptoms.
Can I have just one drink on metronidazole?
No — even a small amount of alcohol can trigger the disulfiram reaction on metronidazole. There is no safe minimum. Do not drink any alcohol during your course or for 48 hours after.
What if I accidentally drank alcohol on metronidazole?
If you have already consumed alcohol while on metronidazole, stay in a cool place, drink water, and rest. Symptoms usually peak within 30-60 minutes and subside over 2-4 hours. If you experience severe chest pain, difficulty breathing, or lose consciousness, call 999 (UK) or 911 (US) immediately.
Is metronidazole 500mg and alcohol reaction the same as 200mg?
Yes — the severity of the reaction depends on the amount of alcohol consumed, not the metronidazole dose. Any dose of metronidazole inhibits ALDH2 and can trigger a reaction with alcohol. Avoid alcohol with any dose.
Can I use alcohol-based mouthwash on metronidazole?
Avoid alcohol-containing mouthwash and any products containing ethanol (including some cough syrups, tonics, and cooking wines). The reaction requires alcohol to be absorbed — using small amounts of mouthwash occasionally is unlikely to cause a full reaction, but it's safest to avoid it.
Metronidazole alcohol interaction — how long does it last?
The acute reaction (nausea, flushing, vomiting) typically lasts 2-6 hours after alcohol exposure. However, the risk of reaction persists for 48 hours after the last metronidazole dose as the enzyme inhibition resolves. Do not drink until 48 hours have passed since your last tablet.