See a doctor

Metronidazole Overview

Metronidazole is an antibiotic, which means it’s used to treat bacterial infections.

Brand Names: Flagyl, Metro, Flagyl IV

Used for: Bacterial infections.

Availability: Prescription.

Dosage: Oral: 7.5 mg/kg orally every 6 hours

Pregnancy: Category B. No proven risk.

Side effects:Dizzy spells, Dry mouth, Symptoms of a cold, such as sneezing or a runny nose, Sore tongue, Swollen glands, Indigestion, Trouble sleeping, Vaginal itching or discharge.

Warnings: Alcohol causes various unpleasant side effects if consumed during your metronidazole treatment..

Notes: Metronidazole might not be suitable for people with certain medical conditions. You should tell your doctor if you suffer from - Liver disease, Crohn’s disease, Blood disorders, Epilepsy, Nerve conditions

Talk to a GP about metronidazole

Take a short consultation with one of our doctors to talk about your condition and get the correct treatment.

Book online appointment

Metronidazole (me troe NI da zole)

Learn About:

How to take - Side Effects - Dosage - Things To Avoid - Pregnancy

There are many different antibiotics to choose from and you’ll need to speak to a doctor to confirm whether metronidazole is the right option for you. Our doctors can discuss your symptoms, explain the possible side effects of the drug and have a prescription sent directly to your preferred pharmacy.

How To Take Metronidazole

Because metronidazole can be used to treat a wide variety of infections, it’s available in different forms.

In most cases, you’ll be given tablets. An extended release capsule is a common method of treatment. In order for it to be effective, this should be swallowed whole so that the drugs can be properly absorbed into your system, and should be taken on an empty stomach, at least two hours either side of a meal.

You can also be given metronidazole via an injection (intravenously), but this tends to be reserved for serious cases and is likely to be done only if you’re already in hospital.

What Does Metronidazole Treat?

Metronidazole can treat a range of bacterial infections. It’s been shown to be particularly effective in tackling infections in the following areas:

  • Respiratory tract (nose, mouth and throat)
  • Skin and soft tissue
  • Stomach
  • Joints
  • Vagina

What Are The Side Effects of Metronidazole?

There are a number of side effects to look out for if you’re taking metronidazole, ranging from mild to severe. The following side effects are reasonably common and should go away once your treatment is over:

Like many antibiotics, metronidazole can also cause bouts of diarrhoea and digestive problems. These are usually mild and, as with the issues described above, should go away once you stop taking the drug.

However, you should speak to a doctor if your diarrhoea is extremely watery, contains blood or is coming out black or tar-coloured, as this could be a sign of a more serious problem.

See a Doctor About Your Metronidazole

Other serious side effects that you should speak to a doctor about urgently include:

  • A tingling feeling in your hands and/or feet
  • Sores around your mouth
  • Back pain
  • Depression
  • Discomfort when urinating
  • Pain in your eyes, poor vision or blindness
  • Slurred speech
  • Mood swings
  • Seizures
  • Twitching
  • Difficulty concentrating
  • High fever
  • Muscle weakness
  • Disorientation
  • Stiff neck
  • Light sensitivity
  • Drowsiness
  • Nausea
  • Vomiting
  • Skin swelling, burning, pain or rash

You must also be aware of signs you’re having an allergic reaction to metronidazole. If you start to have difficulty breathing, or notice swelling around your face, lips or throat, call for emergency medical attention straight away.

Metronidazole Dosage

Given the wide variety of different infections it can treat, it’s impossible to give an ‘average’ dose for metronidazole. Your dosage will be whatever your doctor recommends.

Whatever this is, it’s important that you stick to their instructions for the full course of treatment. Antibiotics tend to improve your symptoms over time, so you shouldn’t stop taking metronidazole because you’re feeling better, nor should you give up if you don’t notice any improvement after a couple of days.

Try not to miss a dose, as this gives the bacteria in your system a chance to regroup and build up a resistance to the metronidazole. Long-term, this could make it a less effective treatment.

If you do accidentally miss a dose, don’t panic. Take it as soon as you realise, unless it’s almost time for your next dose. Don’t take a double dose to compensate, as this won’t make the drug any more effective and will simply increase the likelihood of side effects.


Things To Avoid

Metronidazole might not be suitable for people with certain medical conditions. You should tell your doctor if you suffer from:

These issues don’t necessarily mean you can’t take metronidazole, but they may mean that you can only do so in small doses. You might also need to undergo tests beforehand, or you might have to undergo regular blood tests throughout your treatment.

Metronidazole can also react with a variety of other drugs. If you’re taking any other form of medication, whether it’s over-the-counter or a prescription, it’s vital that you tell your doctor.

Can You Drink Alcohol When You’re On Metronidazole?

Alcohol causes various unpleasant side effects if consumed during your metronidazole treatment, such as:

  • Hot flushes
  • Headaches
  • Vomiting
  • Dizzy spells
  • Nausea
  • Irregular heartbeat
  • Breathing difficulties

Scientists are not sure exactly why this happens, which is why it’s important to be extra cautious. In addition to steering clear of alcohol throughout your treatment, you should also wait until at least three days after your last dose of metronidazole before drinking again.

Is It Safe To Take Metronidazole During Pregnancy?

Metronidazole must not be taken during the first trimester of your pregnancy.

Various studies have been done into the effects of this drug on unborn babies, and one test found a possible increased risk of cleft lip if the mother was taking metronidazole during the first trimester.

As yet, there are no official recommendations regarding trimesters two and three, but given that tests are ongoing, this might be something you wish to discuss with a doctor before proceeding.

Metronidazole has also been shown to contaminate breast milk in breastfeeding mothers, which poses a risk to your baby. You should either stop breastfeeding for the duration of your treatment, or work with your doctor to find a more suitable antibiotic.

See a doctor about Metronidazole
pregnant women

Talk to a doctor Today

If you’re looking for a suitable antibiotic to treat your infection and would like to know more about metronidazole, book an appointment with one of our doctors today. You’ll be able to discuss your symptoms, any other medication you’re taking and the possible side effects you could experience.

Our UK-based GPs have the knowledge and experience to recommend the most suitable antibiotic for you.

See a doctor

Prescriptions, Fit Notes & Referral Letters at the Push of a Button

With Push Doctor you can get the medical advice and help that you need.

1. Book an appointment

Be seen in minutes, or choose a time that suits you.

2. Speak to a doctor online

Talk face-to-face with a UK GP through our app or website.

3. Start feeling better

Receive medical advice, instant prescriptions, referrals and fit notes.
See a doctor