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What does it do?

Metronidazole is used to treat and prevent infections.

How should you take it?

Take metronidazole regularly as directed. Keep taking it until the course is finished, even if you start to feel better.
Take the tablets with food and a glass of water.
Take the liquid on an empty stomach (one hour before or two hours after food). Measure the liquid carefully with an oral syringe or measuring spoon.

What if you forget a dose?

Take the missed dose as soon as possible and continue as directed.

Can you take other medicines?

Some medicines available without a prescription may react with metronidazole including:

  • medicines containing alcohol (e.g. some cough mixtures)

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Numbness or tingling of the fingers or toes


Changes in vision

Skin rash

Tell your doctor immediately

Dizziness, headache, drowsiness, tiredness or weakness

Vomiting, diarrhoea, loss of appetite

Metallic taste, furry tongue

Vaginal itch or discharge (vaginal thrush)

Tell your doctor if troublesome


Take with food (tablet only)

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • Tell your doctor if you have liver or blood problems, multiple sclerosis, or if you have ever had a seizure.
  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
  • Do not drink alcohol while being treated with metronidazole. The combination of metronidazole and alcohol may cause severe nausea and vomiting, facial flushing and headache. Avoid drinking alcohol for at least 24 hours after the course is finished.
  • Your urine may become darker while taking metronidazole.

This leaflet contains important, but not all, information about this medicine.

Prepared by the PILs Committee at Christchurch Hospital, Canterbury District Health Board, New Zealand. October 2017

For more general information about this sheet annd its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at the Canterbury District Health Board. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed