Experiences with
Mebendazole

Mebendazole is a type of medicine for treating worms.

It's used mainly for infections of the gut such as threadworms (sometimes known as pinworms) and other less common worm infections (whipworm, roundworm and hookworm).

It works by stopping worms from using sugar (glucose) to live. This kills the worms.

You can buy mebendazole from a pharmacy for adults and children aged 2 years and over. It's also available on prescription for children aged 6 months and over.

It comes as chewable tablets or a liquid that you swallow.

Who can take mebendazole

Most adults and children from the age of 2 years can take mebendazole.

Younger children between the ages of 6 months and 2 years can take it if it's prescribed by a doctor.

Who may not be able to take mebendazole

Mebendazole is not suitable for some people. To make sure it's safe for you, tell a pharmacist or doctor if you:

have ever had an allergic reaction to mebendazole or any other medicine
are pregnant or breastfeeding

Dosage

A doctor or pharmacist will tell you how much mebendazole to take, depending on the type of worms you have.

If you have threadworms (also called pinworms) you'll usually take a single dose. If you live with anyone else, they will need to be treated at the same time because threadworms can spread easily.

A doctor or pharmacist may suggest you repeat the dose after 2 weeks to stop you from getting threadworms again. This is because the medicine kills the worms but not their eggs.

For other worms such as whipworm, roundworm and hookworm, follow your doctor's instructions on how to take mebendazole. Usually you need to take a dose 2 times a day for 3 days.

How to take it

Chew the tablet or swallow it whole with a drink of water, juice or milk. You can take it with or without food.

If you're taking the liquid, it comes with a plastic spoon to measure the dose. If you do not have a spoon, ask your pharmacist for one. Do not use a kitchen teaspoon as it will not measure the right amount.

If you forget to take it

If you're taking mebendazole 2 times a day and you miss a dose, take it as soon as you remember, if it's within 4 hours of when the dose was due. If you remember more than 4 hours after your dose was due, skip the missed dose and just take your next dose at the usual time.

Do not take 2 doses to make up for a forgotten one.

If you take too much

Taking an extra dose of mebendazole is unlikely to harm you.

However, you may get side effects such as:

stomach cramps
feeling or being sick (nausea or vomiting)
diarrhoea

your child is under 2 years old and takes an extra dose of mebendazole
you've taken an extra dose of mebendazole and have side effects
you've taken more than 1 extra dose

Get help from 111 online or call 111. Call 111 if you need advice for 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 mebendazole packet or leaflet inside it, any remaining medicine, and any other medicines you take.

Common side effects

These common side effects of mebendazole happen in more than 1 in 100 people. There are things you can do to help cope with them:

Try to rest. It can help to eat and drink slowly and have smaller and more frequent meals. Placing a heat pad or covered hot water bottle on your stomach may also help.

If you're in a lot of pain, speak to a doctor or pharmacist.

Stick to simple meals and avoid rich or spicy food. It might help to take mebendazole after you've eaten to see if that helps ease the symptoms.

Drink plenty of water or other fluids to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.

Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor first.

If you take the combined pill or progestogen-only pill and you have severe diarrhoea for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet to find out what to do.

Speak to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.

Serious side effects

Stop taking mebendazole and call a doctor or call 111 straight away if the whites of your eyes turn yellow, or your skin turns yellow although this may be less obvious on brown or black skin. These can be signs of liver problems.

you or your child has a fit or seizure

Find your nearest A&E

Meds - serious side effects A&E safety messaging

It happens rarely but it's possible to have a serious allergic reaction (anaphylaxis) to mebendazole.

Meds New IA (H4) - serious allergic reaction

These are not all the side effects of mebendazole. For a full list see the leaflet inside your medicines packet.

Mebendazole and pregnancy

Mebendazole can be used during pregnancy, if necessary. However, threadworms are not dangerous to you or your baby. It is better to try to treat worms without taking a medicine first, particularly during the first 12 weeks of pregnancy when your baby is developing.

It's important to:

wash your hands and scrub under your fingernails – particularly before eating, after using the toilet or after changing nappies
bathe or shower every morning
rinse toothbrushes before using them
keep fingernails short
wash sleepwear, sheets and towels regularly
disinfect kitchen and bathroom surfaces
vacuum regularly and dust using a damp cloth

These methods usually get rid of worms within 6 weeks. If they do not work or you are unable to do this, speak to your doctor or pharmacist about using mebendazole.

If you have another type of worm infection such as roundworm or hookworm, speak to a doctor about the best way to treat it.

Mebendazole and breastfeeding

If your doctor or health visitor says that your baby is healthy, it's OK to take mebendazole while breastfeeding.

Mebendazole only passes into breast milk in tiny amounts, and your baby will not be able to absorb a lot into their body from the breast milk. It has not been known to cause any side effects in breastfed babies.

If you notice that your baby is not feeding as well as usual, or if you have any other concerns about your baby, talk to your health visitor, midwife or doctor as soon as possible.

Mebendazole and fertility

There's no evidence to suggest that taking mebendazole reduces fertility in either men or women.

Meds New IA (H2) - Pregnancy non-urgent care card

Cautions with other medicines

Some medicines and mebendazole can affect each other.

Check with a pharmacist or doctor if you're taking:

metronidazole – a medicine usually used for bacterial or protozoan infections
cimetidine – usually used for too much stomach acid

Mixing mebendazole with herbal remedies or supplements

There's not enough information to say that complementary medicines, herbal remedies and supplements are safe to take with mebendazole. They're not tested in the same way as pharmacy and prescription medicines. They're generally not tested for the effect they have on other medicines.

Meds New IA (H2) - Cautions with other medicines alert