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Metronidazole 400mg tablets
  • Metronidazole 400mg tablets

Metronidazole 400mg Tablets

From £14.99

Medication features

  • Effective treatment for genital infections
  • Some infections can be treated with a single dose
  • Can be used as a treatment of a 2 week course
  • For gum and teeth infections
  • Treats stomach ulcers caused by Helicobacter pylori
  • Prevent infections occurring after operations
Note: Packaging/Manufacturer may vary


Bacterial Vaginosis Doctor Service

Metronidazole tablets contain metronidazole as an active ingredient, which belongs to the group of medicines called antibiotics. It works by killing bacteria and parasites that cause infections in your body. 

Metronidazole is an antibiotic used to treat bacterial vaginosis. Metronidazole tablets kill the bacteria which cause the vaginal infection. Bacterial vaginosis is a common condition, which affects many women.

There are many different bacteria and fungi that are naturally present in the vagina, called flora. Normal flora helps to keep the vagina healthy and prevent infections. However, sometimes, this balance of flora is thrown off, causing bacterial vaginosis.

Bacterial vaginosis is not a sexually transmitted infection (STI) and so can also affect women who aren't sexually active. BV can, however, be triggered by sex and can increase the risk of contracting an STI.

What Are The Symptoms Of Bacterial Vaginosis?

  • A white or grey discharge with a 'fishy' smell
  • Discharge that's thin or watery
  • Usually there's no redness or soreness with BV. Half of women with BV don’t have any symptoms.

Metronidazole Tablet Also Can Be Used To Treat:

  • infections, caused by bacteria of the blood, brain, bone, lung, stomach lining and pelvic area, following childbirth or in a wound following an operation
  • gum and teeth infections
  • infected leg ulcers or pressure sores
  • urinary or genital infections caused by a parasite, Trichomonas
  • genital infection in women caused by bacteria
  • the parasitic diseases amoebiasis
  • the disease giardiasis
  • stomach ulcers caused by Helicobacter pylori
  • or prevent infections occurring after operations.

It's also used to treat infected insect bites, skin ulcers, bed sores and wounds, and to treat and prevent bacterial and parasitic infections.

Metronidazole is only available on prescription. The form your doctor prescribes, the dose and how long you'll need to take the medicine depends on the type of infection and how serious it is. Some infections can be treated with a single dose, while others may need a 2 week course.


What is Bacterial vaginosis?

Bacterial vaginosis occurs when the normal balance of bacteria in your vagina is disturbed. Numerous types of bacteria naturally occur in the vagina without being harmful or causing symptoms. If numbers of certain bacteria increase or decrease, this balance is disrupted, which can lead to bacterial vaginosis.

BV is not dangerous. In fact, many women have it without noticing any symptoms. You only need to get treated if you are experiencing symptoms. In many cases, BV heals by itself as the natural balance in your vagina is restored.

Bacterial vaginosis can lead to complications during pregnancy. It is important that you get tested and treated if you are pregnant and experiencing BV symptoms.

How do I know if I have Bacterial vaginosis?

If you have had bacterial vaginosis before, you will most likely be familiar with the symptoms.

However, there are a number of conditions which cause very similar symptoms. Many sexually transmitted infections, for example gonorrhea and chlamydia, also cause discharge. Bacterial vaginosis is also easily confused with thrush (also known as yeast infection).

If you notice discharge and have had unprotected sex with a new partner in the past months, you need to get an STI test to make sure you have not been infected with an STI.

If you are experiencing symptoms such as an itch or pain while urinating, then your symptoms are not caused by bacterial vaginosis. Bacterial vaginosis is not commonly associated with itching, pain or irritation.

If you are unsure as to what is causing your symptoms you can visit your GP for a test. Your GP will collect a sample of the discharge to confirm the diagnosis.

Which symptoms are typical for BV?

The most common symptoms associated with bacterial vaginosis are vaginal discharge and a fishy smell. The symptoms vary and they can be very mild. The discharge can either be thin and watery or of a greyish or white colour.

The bacteria which cause BV do not cause any symptoms in men. Men do not need to worry about BV, even if their partner has it.

Is Bacterial vaginosis a sexually transmitted disease?

Bacterial vaginosis is not a sexually transmitted infection, although it causes very similar symptoms as some of the most common STIs. If you have had unprotected sex and think you have BV, you should get tested for STIs to ensure you get the correct treatment.

Although BV is not a sexually transmitted disease, having sex without a condom and having sex with multiple partners increases your risk of BV. If you repeatedly suffer from bacterial vaginosis you may find it helpful to use a condom during sex to avoid recurrent bouts.

What are the risk factors for getting BV?
  • Vaginal douching
  • STIs
  • Being sexually active
  • Having a new partner
  • A copper intrauterine contraceptive device (known as an IUD)
  • Bubble baths
  • Smoking.
How can I help prevent BV?

If you're getting BV often, see if the following things help to avoid another episode. Otherwise, speak to your GP who'll be able to make sure that you're not getting symptoms from something other than BV.

  • Using condoms can help protect against BV
  • Avoid using vaginal deodorants, perfumed soaps or douches
  • Use water and plain soap to wash your genital area
  • Take a shower instead of baths
  • Don't smoke.

Side Effects

Like all medicines, this medicine can cause side effects although not everybody gets them.

Stop taking Metronidazole and see a doctor or go to a hospital straight away:

  • If you get swelling of the hands, feet, ankles, face, lips or throat which may cause difficulty in swallowing or breathing. You could also notice an itchy, lumpy rash (hives) or nettle rash (urticaria). This may mean you are having an allergic reaction to Metronidazole.
  • If you develop skin rashes with blistering, peeling or bleeding of the skin around the lips, eyes, mouth, nose and genitals. You may also have u-like symptoms and a high temperature.
  • If you get a fever, stiff neck, headache, see or hear things that aren't there. You might also have problems using your arms and legs, problems with speaking or feel confused.

Talk to your doctor straight away if you notice the following side effects:

  • Yellowing of the skin and eyes. This could be due to a liver problem
  • Unexpected infections, mouth ulcers, bruising, bleeding gums, or severe tiredness. This could be caused by a blood problem.
  • Severe stomach pain which may reach through to your back (pancreatitis).

Tell your doctor or pharmacist if you notice any of the following side effects:

  • Mental problems such as feeling confused and seeing or hearing things that are not there (hallucinations)
  • Fits (convulsions)
  • Feeling sleepy or dizzy
  • Problems with your eyesight such as blurred or double vision
  • Headache
  • Liver problems: Darkening of the urine, Pains in the muscles or joints.

For a full list of side effects, read the Patient Information Leaflet.

If you get any side effects, talk to your doctor, our Rightdose pharmacists or nurse. This includes any possible side effects not listed in this leaflet.

You can help to make medicines safer by reporting any side-effects to the Yellow Card Scheme at www.mhra.gov.uk/yellowcard.


Info Leaflet

Before taking any medication, it is important to read the Patient Information Leaflet. You can find information leaflets for your medicines by typing them into the search bar at medicines.org, or by contacting us. 

Patient Information Leaflet Metronidazole Film-coated Tablets

Do not take Metronidazole tablets: 

If you are allergic to metronidazole or any of the other ingredients of this medicine. Signs of an allergic reaction include: a rash, swallowing or breathing problems, swelling of your lips, face, throat or tongue.
If you are not sure if any of the above applies to you, talk to your doctor or pharmacist before taking your medicine. Do this even if they have applied in the past.

Keep this medicine out of the sight and reach of children.

How to store Metronidazole Tablets

  • Do not store above 25°C in original packaging. Protect from light
  • Do not use this medicine after the expiry date shown on the pack. The expiry date refers to the last day of that month.
  • Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.

Other medicines and Metronidazole Tablets

Please tell your doctor or pharmacist if you are taking or have recently taken any other medicines. This includes medicines obtained without a prescription, including herbal medicines. This is because Metronidazole can affect the way some other medicines work. Also, some other medicines can affect the way Metronidazole works. In particular, tell your doctor if you are taking:

  • Anti-coagulants (blood thinning agents), such as warfarin. The dosage of warfarin may need to be reduced if you are taking this drug.
  • Lithium for mental illness. If taken at the same time as metronidazole, the kidneys may be affected.
  • Medicines used to treat epilepsy, such as phenytoin, primidone, phenobarbitone.
  • 5 fluorouracil for cancer.
  • Busulfan for leukaemia (cancer of the blood cells).
  • Ciclosporin - to prevent the rejection of organs after transplant.
  • Disulfiram for alcoholism If you are not sure, talk to your doctor or pharmacist before taking metronidazole.

Pregnancy and breastfeeding

Ask your doctor or pharmacist for advice before taking this medicine if:

  • You are pregnant, might become pregnant or think you may be pregnant. Metronidazole should not be taken during pregnancy unless considered absolutely necessary
  • You are breast-feeding. It is better not to use Metronidazole if you are breast-feeding. This is because small amounts may pass into the mother's milk.

Driving and using machines while taking Metronidazole you may feel sleepy, dizzy, confused, see or hear things that are not there (hallucinations), have fits (convulsions) or temporary eyesight problems (such as blurred or double vision). If this happens, do not drive or use any machinery or tools.


Before taking any medication, it is important to read the Patient Information Leaflet. You can find information leaflets for your medicines by typing them into the search bar at medicines.org, or by contacting us.


Always use this medicine exactly as described in the patient information leaflet or as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure. It is important to finish a full course of treatment. 

  • Swallow the capsule whole with a glass of water.
  • Do not crush or chew the tablets.
  • Take these tablets during or just after a meal.

The dose of metronidazole and the length of your treatment will depend on your needs and the illness being treated.

The usual dose for adults is given below:

To treat bacterial infection - Adults:

  • The initial dose is 800mg.
  • After 8 hours take another dose of 400mg and repeat this dose every 8 hours.

To prevent infections from happening after surgery - Adults:

  • Start taking metronidazole Tablets 24 hours before your operation.
  • Take 400 mg of metronidazole every 8 hours.
  • After the operation you may be given Metronidazole either through a drip into a vein or rectally as a suppository until you are able to take tablets again.

Other types of infections:

For treatment of other infections caused by parasites and some bacteria your doctor will decide how much metronidazole you need to take and how often. This will depend on your illness and how bad it is. The pharmacist's label on the packaging will tell you how many tablets to take and how often to take them.

People having kidney dialysis: Kidney dialysis removes metronidazole from your blood. If you are having kidney dialysis you must take this medicine after your dialysis treatment.

People with liver problems: Your doctor may tell you to use a lower dose or to use the medicine less often.

If you take more Metronidazole Tablets than you should

  • contact your doctor or nearest hospital emergency department immediately. Always take the box, this leaflet and any tablets that are left over with you, if you can. This is so the doctor knows what you have taken.

If you forget to take Metronidazole Tablets:

  • take it as soon as you remember and carry on as before. If it is almost time for your next dose, skip the forgotten dose and continue as usual. Do not take a double dose to make up for a forgotten dose.

Metronidazole Tablets with food and drink

  • Do not drink any alcohol while you are taking Metronidazole and for 48 hours after finishing your course. Drinking alcohol while using Metronidazole might cause unpleasant side effects, such as feeling sick (nausea), being sick (vomiting), stomach pain, hot flushes, very fast or uneven heartbeat (palpitations) and headache.


Warnings and precautions

Talk to your doctor or pharmacist before taking Metronidazole Tablets:

  • if you are having kidney dialysis.
  • if you have or have ever had a liver problem.
  • if you have a disease of nervous system.

If you are not sure if any of the above applies to you, talk to your doctor or pharmacist before taking your medicine. Do this even if they have applied in the past. Cases of severe liver toxicity/acute liver failure, including cases with a fatal outcome, in patients with Cockayne syndrome have been reported with products containing metronidazole.

If you are affected by Cockayne syndrome, your doctor should also monitor your liver function frequently while you are being treated with metronidazole and afterwards.

Tell your doctor immediately and stop taking metronidazole if you develop:

  • Stomach pain, anorexia, nausea, vomiting, fever, malaise, fatigue, jaundice, dark urine, putty or mastic coloured stools or itching.



The active substance is metronidazole. Each Metronidazole  film-coated tablet contains 400 mg of Metronidazole.

The other ingredients are Anhydrous calcium hydrogen phosphate, Maize starch, Povidone, Crospovidone, Microcrystalline cellulose, Colloidal anhydrous silica, Magnesium stearate, Hypromellose and Polyethylene glycol.

What Metronidazole tablet looks like and contents of the pack

400mg: white to off white colored, caplet shaped (17.00 x 6.00 mm) film-coated tablets, debossed “400” on one side and plain on other side.

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