Metronidazole 400mg Tablets

Metronidazole is an antibiotic which can be used to treat a range of infections — it is often used as a treatment for bacterial vaginosis in women — but it is also the most effective treatment for trichomoniasis in both women and men. A 7-day course of Metronidazole (which is taken orally twice a day) will usually clear a trichomoniasis infection fully.

Trichomoniasis (also known as trichomonas or trich) is a non-viral sexually transmitted infection (STI) which is spread through unprotected sex or sharing sex toys. Symptoms of trich include abnormal, foul-smelling discharge from the genitals, pain when urinating, and soreness or redness in the genital area, although many people who have it — particularly men — will present no symptoms at all.

Alternatives to Metronidazole for treating Trichomoniasis

Most people who have been diagnosed with trichomoniasis will be prescribed Metronidazole, as this is the most effective way to treat the condition.

However, when taking trichomoniasis or treatment for any other STI such as chlamydia, gonorrhoea, or genital warts, it’s important to take the following measures to aid treatment prevention:

• Use a condom when you have sex (remember that oral contraceptives do not provide protection from STIs)
• Avoid sharing sex toys (wash them between use or cover them with a fresh condom if you do)
• Practise good hygiene by keeping your genitals clean before and after sex
• Limit your number of sexual partners
• Get tested regularly for STIs

How to take Metronidazole to treat Trichomoniasis

Swallow one Metronidazole tablet with water twice daily for 7 days, preferably with or after food. To ensure the infection doesn’t come back, you should always complete the full course of antibiotics as prescribed by your doctor, even if you feel your symptoms have improved earlier than this.

You should not drink alcohol while taking Metronidazole Tablets or for 48 hours after taking your last dose. You should also speak to your doctor before taking Metronidazole if you are pregnant or breastfeeding.

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 currently undergoing kidney dialysis
• You have a disease of the nervous system

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

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

Metronidazole and alcohol

You should not drink alcohol while taking Metronidazole Tablets, or for 48 hours after completing the course. Drinking alcohol while taking Metronidazole can lead to unwanted side effects such as nausea, vomiting, flushing, stomach pain, palpitations, and headaches.

Metronidazole and pregnancy

There’s no scientific evidence to suggest that Metronidazole is harmful to an unborn baby. However, you should consult your doctor before taking Metronidazole Tablets during pregnancy or while breastfeeding, as this has not been fully studied. Refer to our Metronidazole and pregnancy guide for more information.

Metronidazole ingredients

The active ingredient in Metronidazole Tablets 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).

Metronidazole side effects

Some users may experience side effects when using Metronidazole for STD treatment. Side effects are less likely when using a low dose or when taking Metronidazole with or after food.

Common side effects can include:

• Numbness, tingling, pain, or weakness in the arms or legs
• A furred tongue or an unpleasant taste in the mouth
• Nausea and vomiting
• Upset stomach and diarrhoea
• Appetite loss
• Fever
• Depression
• Pain in the eyes (optic neuritis)

Rarer side effects may include dizziness, drowsiness, flushing, joint pain, or headaches, among others. If you experience any side effects when taking Metronidazole for trich — including any not listed here — you should consult your doctor or pharmacist.

For more information, read our in-depth guide to Metronidazole side effects. If you suffer a severe allergic reaction (such as having difficulty breathing), you should go to your local A&E department straight away.

• Metronidazole Patient Information Leaflet: https://www.medicines.org.uk/emc/files/pil.11952.pdf