Metronidazole

Metronidazole is not suitable for some people. For example, check with your doctor if you have liver problems or you're having dialysis.

Metronidazole comes as tablets, a liquid, skin gel, vaginal gel, skin cream and suppositories. Follow the instructions that come with your medicine.

Side effects of metronidazole include feeling or being sick, diarrhoea and a metallic taste. More serious side effects can happen in rare cases.

Metronidazole can be taken during pregnancy. Check with a pharmacist or doctor first.

Metronidazole cream or gel is OK when breastfeeding. Tablets, suppositories or injections are OK for a short time. Check with a doctor or pharmacist.

It can cause problems to take or use metronidazole with some other medicines, such as warfarin, lithium or phenytoin.

Most adults and children can take metronidazole.

Metronidazole is not suitable for some people.

To make sure it's safe for you, tell your doctor if you:

• have ever had an allergic reaction to metronidazole or any other medicine
• are pregnant or breastfeeding
• feel you will not be able to stop drinking alcohol while using metronidazole
• are having blood tests – metronidazole can interfere with the results of some tests

If you are taking the tablets, liquid or suppositories, you should also tell your doctor if you:

• are having dialysis
• have liver problems
• have a disease of the nervous system

If you are using the vaginal gel, you should also tell your doctor if you:

• think you may have vaginal thrush
• are due your period while on treatment

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.

There are things you can do to help cope with these common side effects of metronidazole.

Stick to simple meals and do not eat rich or spicy food. Always try to take your metronidazole after a meal or snack.

If you're being sick, try small frequent sips of water to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.

Contact your doctor for advice if you're being sick for more than 24 hours.

If you take the combined pill or progestogen-only pill and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.

Drink lots of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.

Contact your doctor for advice if your diarrhoea continues for more than 24 hours. Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.

If you take the combined pill or progestogen-only pill and you have severe, watery diarrhoea or any diarrhoea that lasts for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet for advice.

Drink plenty of water and eat plain foods that you usually enjoy.

If your tongue is very furry, this could be a sign of thrush. Ask your pharmacist or doctor for advice.

If you're using metronidazole cream or gel, you may experience dry skin, itching, discomfort or irritation, or redness (this may be harder to see on brown or black skin).

Try using the cream or gel less often (maybe once a day instead of twice, or every other day), or you could stop using it for a few days until the irritation goes away and then try using it again. If the irritation does not go away, stop using the cream or gel and speak to your doctor.

Talk to your doctor or pharmacist if this advice does not help and a side effect bothers you or does not go away.

You may be able to use metronidazole while you're pregnant.

If you're trying to get pregnant or you're already pregnant, talk to your doctor about whether taking metronidazole is right for you.

If your baby is healthy, it's OK to take metronidazole while you're breastfeeding. Always check with a pharmacist or doctor before taking it.

When metronidazole is taken by mouth, or as suppositories, or injected, it passes into breast milk in fairly small amounts. It has been widely used for many years while breastfeeding and it's unlikely to cause side effects in your baby, but a few babies have had diarrhoea.

It's best to take metronidazole only for a short time. If you need to take it for longer than a few weeks, talk to your doctor or pharmacist.

When metronidazole is used on your skin, or as a vaginal gel, it is not likely to get into your breast milk, and you can use it for longer than a few weeks if you need to.

When using the cream or gel, be careful that your baby does not come into contact with the areas of your body you have put it on. Always wash your hands after you have applied the cream, gel or vaginal gel before touching your baby.

It's important to keep monitoring your baby if you're breastfeeding and taking metronidazole by mouth, as suppositories, or as an injection.

Contact your healthcare professional or call 111 as soon as possible if you notice that your baby:

• is not feeding as well as usual or not putting on weight as you'd expect
• has a stomach upset
• has oral thrush (a fungal infection in their mouth)

If your baby has any symptoms that are not listed, or if you're worried about them, you can also call 111 or contact any healthcare professional.

Carry on taking metronidazole and keep breastfeeding as usual until you've got advice about your baby's symptoms.

Metronidazole may not mix well with some other medicines. This can be a problem with metronidazole tablets, suppositories, liquid or vaginal gel. It is not usually a problem if you are using a skin gel or cream, as only a small amount of metronidazole is absorbed into the body.

Check with a pharmacist or your doctor if you're taking any other medicines, including:

• warfarin, a medicine that helps to treat and prevent blood clots
• lithium, used to treat some types of mental health conditions
• disulfiram, used to help people stay off alcohol
• phenytoin or phenobarbitone, used to treat epilepsy
• ciclosporin, used to reduce the activity of the immune system
• fluorouracil or busulfan, used to treat some types of cancer
• any medicines that you take as a liquid, in case these contain alcohol

These are not all the medicines that may cause problems if you take them with metronidazole. For a full list, see the leaflet inside your medicine packet.