Metronidazole comes as tablets, liquid, skin gel, vaginal gel, skin cream and suppositories.
The type of metronidazole your doctor prescribes, the dose and how long you need to take it for depends on the type of infection you have and how serious it is.
Always follow the instructions from your doctor or pharmacist, or the leaflet in the medicine packet.
Dosage and how to take metronidazole
Dosage for tablets, liquid or suppositories
Some infections can be treated with a single dose, while other infections may need a 2-week course. If you're prescribed a 2-week course of tablets, you'll usually take them 2 or 3 times a day.
Children's doses are lower and depend on the age or weight of your child.
Your doctor may prescribe metronidazole suppositories if you have difficulty swallowing medicines. You'll usually use them 3 times a day, although you may be told to use them twice daily if you are going to continue treatment with suppositories for longer than 3 days.
Dosage for cream or gel
If you're prescribed metronidazole cream or gel for rosacea, you'll normally use it twice a day for about 2 months. Treatment can sometimes last longer. It is important to continue using the treatment until your doctor tells you to stop.
If you're using the cream or gel for a skin infection, or infected ulcers or wounds, you'll usually put it on once or twice a day.
Follow your doctor or pharmacist's instructions and continue treatment until your infection has healed.
Dosage for vaginal gel
For treating bacterial vaginosis, you'll use an applicator to put the metronidazole gel into your vagina.
The usual dose for treating bacterial vaginosis is 1 applicator full, every night for 5 nights.
How to take tablets
Swallow the tablets whole with a drink of water, with or just after you've eaten some food.
How to take liquid
Metronidazole liquid does not need to be taken with or after food.
Shake the bottle before you measure out your dose.
This medicine comes with a plastic syringe or spoon to help you measure out the right dose. If you do not have one, ask your pharmacist for one. Do not use a kitchen teaspoon as it will not measure the right amount.
How to use suppositories
Read the instructions in the leaflet inside the packet. This will explain how to use the suppository.
Take the wrapping off and push a suppository gently into your bottom (anus).
Remember to wash your hands before and after you insert the suppository.
When to take tablets, liquid or suppositories
If you need to take several doses of metronidazole tablets, liquid or suppositories every day, try to space the doses evenly. For example, if you take your medicine 3 times a day, this could be first thing in the morning, mid-afternoon, and at bedtime.
How to put on cream or gel
Put a thin layer of cream or gel onto the area you're treating and rub it in very gently.
Try to avoid getting it into your eyes, as it can sting. If you do get some in your eye, wash it out immediately with cold water.
Remember to wash your hands before and after using it.
How to use vaginal gel
Follow the instructions that come in the packaging along with your medicine. This will tell you how to fill the applicator with gel and put it into your vagina.
Do not have sex while using the vaginal gel.
It's recommended that you do not use the gel while having your period or if you have, or think you may have, vaginal thrush.
How long to take or use it for
It's very important to keep taking or using metronidazole for as long as your doctor has prescribed it.
Important: Finishing your course of metronidazole
It's important to carry on taking or using metronidazole until you have finished the course, even if you feel better. If you stop your treatment early, the infection could come back.
If you forget to take or use it
If you miss a dose of metronidazole, take it as soon as you remember, unless it's nearly time for your next dose. In this case, just leave out the missed dose and take your next dose at the usual time.
Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.
If you're using cream or gel for skin, do not use it more than twice a day unless your doctor tells you to.
If you're using vaginal gel, do not use it more than once a night.
If you often forget doses, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to remember your medicines.
If you take or use too much metronidazole
Taking an extra dose of metronidazole tablets, liquid or suppositories is unlikely to harm you or your child.
If you put on too much cream or gel, it's unlikely to harm you. Wipe off any extra cream with a clean tissue or wash it off with warm water.
If you use too much vaginal gel it's unlikely to harm you.
Talk to your pharmacist or doctor if you're worried.
Urgent advice: Contact 111 for advice now if:
- you or your child take more than 1 extra dose of metronidazole tablets, liquid or suppositories and have any new symptoms
- you or your child swallow a lot of metronidazole cream or gel
Call 111 or get help from 111 online. Call 111 if you're asking about a child under 5 years old.
If you need to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.
Bring the metronidazole packet or leaflet inside it, any remaining medicine, and any other medicines you take.