Metronidazole 400mg Tablets

How does Metronidazole work?

Bacterial vaginosis is thought to be caused by a change in the natural balance of bacteria that live in the vagina. Because Metronidazole has antibiotic properties, it helps to kill excess bacteria and return the balance to normal, reducing the symptoms.

Metronidazole (also spelt Metronidazol) can be used to treat a number of different bacterial infections, though we only prescribe it to treat Bacterial Vaginosis (BV) in women. It is an effective BV treatment that can typically clear symptoms in two to three days and should be taken for the full course.

To learn more about Metronidazole, visit our “What is Metronidazole?” page.

Buying Metronidazole online

Metronidazole is suitable to buy online if you have previously suffered from bacterial vaginosis that has been diagnosed and successfully treated by your GP.

You may qualify for BV treatment online if you have:

• Developed vaginal symptoms such as a fishy odour and a thin discharge
• Had bacterial vaginosis diagnosed by your doctor
• Had a positive home test for bacterial vaginosis
• Had positive results using Metronidazole prescribed for bacterial vaginosis

If you have not suffered from BV before, your symptoms are not typical of BV, or you have had a negative test result, you should see your GP or visit a local sexual health clinic for further investigation.

If you are not sure whether your symptoms are caused by bacterial vaginosis, you can use a Canestest Home Kit to check. Vaginal discharge and odour can be caused by a number of different bacterial infections, including STIs, so it's important to make sure you correctly identify your condition: only then can you find the right treatment.

Treating recurrent BV with Metronidazole

Metronidazole tablets can also be used to treat recurrent bacterial vaginosis. It is not uncommon for BV to return within three months of first treatment. As long as the first course of Metronidazole was successful and your symptoms are the same as they were before you completed that course, you’re safe to use Metronidazole again.

If you have BV more than twice in 6 months or 4 times in 12 months, you should consult a GP or sexual health clinic.

Can I use Metronidazole to treat thrush?

A yeast infection is not the same as BV. Although both infections can cause similar symptoms, their causes are distinct. A yeast infection (such as thrush) is caused by a fungus overgrowth, whereas BV is caused by bacterial overgrowth. Thrush doesn’t tend to have a fishy odour like BV, but it does produce a distinct discharge that is similar to cottage cheese in appearance.

Thrush can be treated with oral capsules or alternative treatments such as a pessary and cream combo.

Alternatives to Metronidazole

Metronidazole is the only oral option for treating bacterial vaginosis, but there are other treatments available:

• Zidoval is a vaginal gel that contains metronidazole. The gel is inserted into the vagina daily for 5 days and treats the infection locally. It is a prescription-only treatment that can be purchased after a short online consultation.
• Balance Activ BV gel is a non-prescription alternative to treat BV. It helps to lower the pH of the vagina, making conditions more favourable for the regular bacteria that normally live in the vagina to flourish. It can be used alongside Metronidazole

How to take Metronidazole to treat BV

Take 1 oral tablet twice daily for 7 days. Metronidazole should be taken with or after food.
Always ensure that you complete the course, even if you think your symptoms have improved. This will help to prevent the infection from coming back.

You should avoid alcohol while taking Metronidazole and for at least 48 hours after your course has finished. Alcohol can cause a serious interaction with Metronidazole that results in nausea and vomiting.

Metronidazole can interact with alcohol - you should avoid alcohol while you are taking Metronidazole and for 24 hours after you have completed the course. You can read more about Metronidazole and alcohol here.

How can BV be prevented?

BV can affect women of any age, but it is more common in sexually active women during their reproductive years. It is not, however, a sexually transmitted infection (STI). Finding the right treatment, such as Metronidazole tablets, will help clear up symptoms, but there are also things you can do to prevent BV from recurring.

You can lower your risk of contracting BV by:

• Always use condoms when sleeping with multiple sexual partners
• Avoiding using fragranced products in and around your vagina as this can cause irritation. Water is enough to keep your vagina’s bacteria well-balanced.
• Always wipe front to back after using the toilet
• Wearing breathable underwear
• Including probiotics in your diet

Preventative measures can stop BV from recurring, but if your symptoms are already present then a course of medication will be most effective.

Metronidazole ingredients

The active ingredient in this medicine is metronidazole 400mg.

The other ingredients are: Croscarmellose Sodium, Cellulose, Colloidal Silica, Lactose, Magnesium Stearate, Maize Starch, Polyethylene Glycol, Titanium Dioxide (E171), Hydroxypropylcellulose (E463), Methylhydroxypropylcellulose (E464).

Not everyone who uses Metronidazole will experience side effects, but some will. Side effects are less likely when using a low dose (such as the dose for bacterial vaginosis) and when using it with or after food.

Side effects of unknown frequency:

• Numbness, tingling, pain or weakness in the arms or legs
• An unpleasant taste in the mouth
• A furred tongue
• Feeling sick (nausea)
• Being sick (vomiting)
• An upset stomach
• Diarrhoea
• Appetite loss
• Fever
• Feeling depressed
• Pain in your eyes (optic neuritis)

Rare side effects:

• Anaphylactic reactions
• Abnormal laboratory test results
• Blood and bone marrow problems (these may be fatal)
• Brain and central nervous system problems (including neurological problems): seek medical advice if you have symptoms such as fever, paralysis, photosensitivity, balance or coordination problems, a stiff neck, tremors, or epileptic seizures
• Convulsions
• Double vision
• Eye or eyesight problems
• Feeling dizzy
• Feeling drowsy
• Flushing
• Headaches
• Itching
• Jaundice
• Joint pain
• Liver problems
• Muscle pain or tenderness
• Myopia
• Pancreatitis
• Psychotic problems including confusion and hallucinations
• Skin problems
• Skin rash
• Urine colour changes

If you experience any serious side effects, you should contact your doctor for further advice.

You can find out more about your chances of experiencing any of the above in our in-depth guide to Metronidazole side effects. If you suffer a severe allergic reaction (if you’re having difficult breathing, for example), you should go to your local A&E department.

Metronidazole warnings

You should not take Metronidazole tablets if any of the following apply to you:

• You have (or have ever had) a liver problem
• You are having kidney dialysis
• You have a disease of the nervous system
• You are pregnant or breastfeeding

You should not take Metronidazole tablets if you take any of the following medicines:

• Anticoagulants (blood thinning agents), such as warfarin: the dosage of warfarin may need to be reduced if you are taking Metronidazole
• Lithium: if taken at the same time as metronidazole, it can affect the kidneys
• Medicines used to treat epilepsy (e.g. phenytoin, primidone, or phenobarbitone)
• 5-fluorouracil (for cancer)
• Disulfiram (for alcohol abuse)
• Cimetidine (for indigestion and heartburn)

Can you drink alcohol while taking Metronidazole?

You should not drink alcohol during your course of Metronidazole tablets or for 48 hours afterwards. The combination of Metronidazole and alcohol can cause unwanted side effects such as nausea, vomiting, flushing, stomach pain, palpitations and headaches.

Does Metronidazole interfere with contraception?

No - there is no evidence that there is any interaction with oral or other types of hormonal contraception.

Can you use Metronidazole tablets while pregnant?

Metronidazole is used for vaginal infections for which pregnant women may sometimes require treatment, just like any others. The risk of miscarriage while using Metronidazole is thought to be unlikely. There’s no scientific evidence suggesting that Metronidazole is harmful to an unborn baby, but because it has not been fully studied, it’s not possible to say for sure that it’s absolutely safe to use while pregnant. You should consult your doctor if you develop a vaginal infection during pregnancy. Check out our guide on Metronidazole and pregnancy for more information.