Metronidazole and alcohol guide

If you have been prescribed metronidazole to treat bacterial vaginosis (BV), you will likely have heard about the risk of mixing the medication with alcohol.

Whilst it is one of the most well-known warnings in pharmacy practice, many people still wonder why this interaction occurs and what the real risks are.

At Quick Meds, our GPhC-regulated UK pharmacy team is committed to providing evidence-based advice. Here, we’ll explain the science behind the interaction, how long you need to wait before having a drink and what to do if you accidentally have a drink whilst on treatment.

Can You Drink Alcohol on Metronidazole?

The short answer is no. You must completely avoid alcohol whilst taking metronidazole tablets or using metronidazole gel.

This is not general antibiotic advice but rather a critical safety warning. Even small amounts of alcohol can trigger a severe, potentially dangerous reaction in your body. As a precaution, you should also stay away from everyday items that contain small amounts, such as mouthwashers or food sauces.

What Happens if You Drink Alcohol While Taking Metronidazole?

When you drink alcohol, the liver uses a specific enzyme (aldehyde dehydrogenase) to break down a toxic byproduct of alcohol into a harmless substance.

Metronidazole stops this enzyme from working and in doing so, the toxic byproduct builds up in your blood. This triggers what is known medically as a disulfiram-like reaction - named after a drug used to treat alcohol dependence by making people violently ill if they drink.

Symptoms of a Metronidazole Alcohol Reaction

• Severe, persistent nausea.

• Violent vomiting.

• Intense abdominal cramps and stomach pain.

• Sharp, throbbing headaches.

• A rapid or irregular heartbeat.

• Shortness of breath.

• Low blood pressure, dizziness or feeling faint.

The severity of symptoms can vary, depending on how much alcohol you drink and your metabolism. For some, a sip may bring on symptoms within minutes.

How Long After Taking Metronidazole Can You Drink?

As the body takes time to process the medication, it's important to make sure metronidazole is completely cleared from the system before you have a drink.

The 48-Hour Rule

You must wait at least 48 hours (two full days) after your last metronidazole dose, before you can drink alcohol.

How Long Should You Avoid Alcohol After Metronidazole?

Whilst 48 hours is the minimum time, many clinicians recommend waiting up to 72 hours (3 full days), if you have a history of liver issues or are sensitive to medications.

This three day wait makes certain that the drug has completely left the body, and the liver has completely processed the medication, freeing it up to process alcohol safely.

Can You Drink Alcohol on Zidoval Gel?

Zidoval gel contains the same drug - metronidazole 0.75%. As this is applied directly inside the vagina, it works locally. Very little of the drug enters the bloodstream compared to the tablets.

However, as there is still a small amount of absorption, the same safety warning applies. The same disulfiram-like reaction can still occur with the gel. For this reason, you should avoid drinking alcohol for the whole 5-day course and for at least 48 hours after the final application.

Unexpected Alcohol Sources to Avoid

When avoiding metronidazole interactions with alcohol, it's important to consider sources which may not be as obvious as beer, wine or spirits. Always check the labels of foods and healthcare products during your treatment:

• Mouthwashes and breath sprays - many standard mouthwashes contain alcohol. To be safe, switch to alcohol-free alternatives.

• Cough and cold remedies - Liquid cough syrups often use alcohol as a solvent.

• Cooking ingredients - Soy sauce, vinegars, and some dishes like tiramisu or some pasta sauces contain alcohol which doesn’t always completely evaporate during cooking.

What to Do If You Accidentally Mix Them

If you accidentally drink alcohol whilst on metronidazole treatment, stop drinking immediately. Drink plenty of water to remain hydrated and rest in a comfortable position.

If you experience mild symptoms, these should pass on their own as the body metabolises the alcohol.

If however, you experience severe symptoms, including continuous vomiting, chest pain, a racing heart, or breathing difficulties, you should seek immediate medical attention, by calling 999 or visiting Accident & Emergency (A&E).

Where to Buy Metronidazole

If you are suffering from bacterial vaginosis and require treatment, you can purchase metronidazole gel and tablets from Quick Meds - a UK based, GPhC-registered online pharmacy. As prescription-only (POM) treatments, you cannot purchase these over the counter and must complete a consultation first.

Our process makes it easy:

1. Consultation - Complete an online consultation - this asks about your symptoms, your medical history and if you take other medication.

2. Checkout - Add preferred treatment to your basket and securely checkout.

3. Prescriber review. Our UK-based pharmacist prescribers will review your order for safety and suitability.

4. Dispatched. Approved orders are dispatched usually on the same day in plain, discreet packaging, directly to your door.