Metronidazole - Side Effects, Precautions, and Contraindications
Skip Ribbon Commands
Skip to main content


Drug Class: Commonly Known As: Category:

Metronidazole - Side Effects, Precautions, and Contraindications

What side effects can Metronidazole cause?

Common side effects include:

  • Nausea, vomiting, loss of appetite, having a metallic or unpleasant taste in your mouth
    • Take Metronidazole with or after food.
  • Headache
    • May take pain relief medications.
  • Dry skin, redness or itching, skin irritation (for Metronidazole gel only)
    • Use the gel a little less often or stop using it until the irritation settles down. If the irritation is severe or worsens, stop using the medication and seek medical advice
  • Darkening of urine, which is a harmless side effect on its own

Very rarely, Metronidazole may cause severe side-effects that are generally reversible once the medication is stopped. Stop this medication and seek medical advice immediately if you develop any of these symptoms below.

Liver injury with symptoms such as:

  • Dark-coloured or tea-coloured urine with accompanied symptoms as below
  • Pale stools
  • Severe abdominal pain, nausea and vomiting
  • Loss of appetite
  • Yellowing of the skin and eyes

    Neurological disturbances such as:
  • Confusion, hallucinations
  • Disturbances in sight and movements, light sensitivity
  • Numbness
  • Stiff neck, tremors, convulsions, uncontrolled muscle and eye movements

The symptoms of a drug allergy include one or more of the following. If you experience any of these symptoms, you should stop your medicine immediately and see your doctor.

  • Swollen face/eyes/lips/tongue        
  • Difficulty in breathing
  • Skin rashes over your whole body

Before taking Metronidazole , what precautions must I follow?

Inform your healthcare professional if:

  • You are allergic to this medication or any of the other ingredients of this medication.
  • You are pregnant, planning to become pregnant, or breastfeeding. Metronidazole crosses the placenta and may carry risk to the fetus, especially in the first trimester. Metronidazole can be present in significant amounts in the breast milk. It may still be used safely in pregnancy and breastfeeding. Risks and benefits regarding the use of Metronidazole during breastfeeding and pregnancy should be discussed with your doctor.
  • You have taken Disulfiram within the past two weeks.
  • You are taking any other medications, including supplements, traditional medications and herbal remedies.
  • You have liver disease, kidney disease or disease of the nervous system.

What food or medicine must I avoid when I take Metronidazole ?

​Avoid consuming alcohol during the course of antibiotics and for three days after completion of antibiotics. Drinking alcohol with Metronidazole causes an unpleasant reaction which may present with nausea, vomiting, abdominal pain, palpitations (fast heart rate), hot flushes, headaches.


  • Updated on 7/31/2021 12:00:00 AM
  • Article contributed by PSS National Medication Information Workgroup PSS National Medication Information Workgroup
The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

Find Your Medicines