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Can You Mix Metronidazole And Alcohol

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Metronidazole And Alcohol

Metronidazole is a commonly used antibiotic for the treatment of various infections, where anaerobic bacteria are suspected to be causative organisms.

Metronidazole And Alcohol

Some common infections treated with metronidazole are acute dental infections, rosacea, and bacterial vaginosis.

One of the warnings on the dispensing label for this antibiotic includes interaction between metronidazole and alcohol.

This warning states: Do not drink alcohol while taking this medication.

What Is The Reason For Metronidazole And Alcohol Warning?

Alcohol And Drug Metabolism

As with many drugs, alcohol is metabolized (broken down) by the liver. Alcohol can interact with different drugs affecting their metabolism or enhance their effect, for example, increased sedation. Alcohol consumption can increase or decrease the speed of drug metabolism, affecting the concentration of the drug in the body.

The degree of interactions between drugs such as metronidazole and alcohol may affect how much and how often a person drinks. For example, in chronic drinkers (alcoholics), the metabolism of drugs can be reduced when both alcohol and drugs are taken together, resulting in a higher concentration of drugs in the body (Weathermon & Crabb, 1999).

Drinking Alcohol On Metronidazole


Manufacturers of metronidazole advise not to drink alcohol during the treatment and at least 48 hours afterward due to the potential risks of disulfiram-like reactions. Disulfiram-like reactions can be very unpleasant and sometimes very serious if the patient has an underlying medical condition such as coronary artery disease (ibid).

Disulfiram-like reactions include:

  • Flushing due to dilation of blood vessels
  • Headaches
  • Rapid heartbeats
  • Low blood pressure
  • Shortness of breath
  • Nausea, vomiting

The cause of disulfiram-like reactions is increased concentration and accumulation of a toxic compound called acetaldehyde, a product of alcohol metabolism. Metronidazole inhibits aldehyde dehydrogenase, an enzyme responsible for breaking down acetaldehyde.

Genetic variations between people can also affect how much acetaldehyde is accumulated in the body when alcohol is consumed.

Metronidazole And Alcohol Interaction A Myth?

A research paper, Lack of Disulfiram-Like Reaction with Metronidazole and Ethanol, was published in Sage Journals questioning the interaction between metronidazole and alcohol.

This study involved a small sample of 12 healthy individuals, half of whom received a 5-day course of metronidazole and were given alcohol to investigate if metronidazole increased acetaldehyde concentrations in the body, confirmed with blood samples taken from patients.

This study concluded that metronidazole does not have an effect on acetaldehyde concentrations when alcohol is consumed, suggesting that some of the side effects experienced by patients (e.g., headaches) are due to metronidazole itself.

One must note that individuals who participated in this study received a relatively low dose of alcohol 0.4 g/kg; this, for example, would equal 32ml of alcohol for someone with a weight of 65kg. Additionally, this study concluded that disulfiram-like reactions might happen through other mechanisms.

Overall, some studies reporting disulfiram-like reactions experienced by patients taking metronidazole and alcohol exist. These include serious reactions and one death reported. However, none of the available publications provide evidence to support the pharmacological effect of metronidazole & alcohol interaction (Williams & Woodcock, 2000). Patients should always be advised not to drink alcohol whilst taking metronidazole.

Quick FAQ

Can I take metronidazole if I drank last night?
Most antibiotics are safe with alcohol if taken in moderate amounts. Unfortunately, metronidazole is not one of them and can worsen the side effects.
What foods should I avoid while taking metronidazole?
Alcohol, avocados, bananas, chocolate, and salami are a few foods that should be avoided while taking metronidazole. >
When can I drink after taking metronidazole?
Doctors usually recommend waiting for at least 3 days to drink after taking metronidazole
References