Ethosuximide for preventing seizures

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Ethosuximide for preventing seizures

This leaflet is about the use of ethosuximide for preventing seizures. (Seizures may be also called convulsions or fits.)

This leaflet is for parents and carers about how to use this medicine in children. Our information sometimes differs from that provided by the manufacturers, because their information is usually aimed at adults. Please read this leaflet carefully. Keep it somewhere safe so that you can read it again.

Do not stop giving ethosuximide suddenly, as your child may have more seizures.

Name of medicine

Brand names:
Zarontin®, Emeside®

Why is it important for my child to take this medicine?

It is important that your child takes ethosuximide regularly so that they have fewer seizures.

What is ethosuximide available as?

  • Capsules: 250mg
  • Liquid medicine: 250 mg in 5 mL

When should I give ethosuximide?

Ethosuximide is usually given twice each day, once in the morning and once in the evening. Ideally, these times are 10–12 hours apart, for example some time between 7am and 8 am, and between 7pm and 8 pm.

Very occasionally the medicine can be given three times a day (your doctor will tell you if it needs to be given like this). This should be in the morning, early afternoon and at bedtime. Ideally, these times are at least 6 hours apart, for example 8 am, 2 pm and 8 pm.

Give the medicine at about the same time(s) each day so that this becomes part of your child’s daily routine, which will help you to remember.

How much should I give?

Your doctor will work out the amount of ethosuximide (the dose) that is right for your child. The dose will be shown on the medicine label.

Your doctor may suggest that your child starts with a low dose. They may then increase the dose as your child gets used to the medicine and depending on how they respond to it. Your doctor will explain what to do. If you are not sure how much to give, check with your doctor, epilepsy nurse or pharmacist.

It is important that you follow your doctor’s instructions about how much to give.

How should I give it?

CapsuleCapsules should be swallowed whole with a glass of water or juice. Your child should not chew the capsule.

Liquid medicine with oral syringeLiquid medicine: Measure out the right amount using an oral syringe or medicine spoon. You can get these from your pharmacist. Do not use a kitchen teaspoon as it will not give the right amount.

When should the medicine start working?

It may take a few weeks for ethosuximide to work properly, so your child may still have seizures during this time. This is because the amount of medicine has to be increased slowly. Continue to give the medicine in the way that you have been told to by your doctor or epilepsy nurse. Ethosuximide may not stop your child’s seizures completely. If you are worried about whether it is helping, contact your doctor but continue to give the medicine.

What if my child is sick (vomits)?

  • If your child is sick less than 30 minutes after having a dose of ethosuximide, give them the same dose again.
  • If your child is sick more than 30 minutes after having a dose of ethosuximide, you do not need to give them another dose. Wait until the next normal dose.

If your child is sick again, seek advice from your doctor, pharmacist or hospital.

What if I forget to give it?

  • If you usually give it twice a day: If you remember up to 4 hours after you should have given a dose, give your child the missed dose. For example, if you usually give a dose at about 7 am, you can give the missed dose at any time up to 11 am. If you remember after that time, do not give the missed dose. Just give the next dose as usual.
  • If you usually give it three times a day: Do not give the missed dose. Just give the next dose as usual.

Never give a double dose of ethosuximide.

What if I give too much?

You are unlikely to do harm if you give an extra dose of ethosuximide by mistake. If you are concerned that you may have given too much, contact your doctor or local NHS Services (see details at end of leaflet). Have the medicine or packaging with you if you telephone for advice.

Are there any possible side-effects?

We use medicines help our children, but sometimes they have other effects that we don’t want (side-effects).

Side-effects that you must do something about

If your child starts to have more fits (seizures) than usual, contact your doctor or take them to hospital straight away.

If your child develops a fever (temperature above 38°C), sore throat, mouth ulcers, bruising or bleeding, contact your doctor or take them to hospital straight away.

Other side-effects you need to know about

Ethosuximide usually causes only mild side-effects, which should get better as your child’s body gets used to the medicine. If they are still a problem after 2 weeks, or you are worried, contact your doctor, but continue to give ethosuximide.

  • Your child may feel sick (nausea) or be sick (vomit) or have stomach ache or diarrhoea, or go off their food.
  • Your child may have a headache or feel dizzy or sleepy (drowsy), and they may have sleep disturbances such as difficulty getting to sleep.
  • They may have hiccups.
  • Your child may seem less alert than normal, and may say they cannot think clearly, or their coordination may be affected (they may seem clumsy). They may also have changes in mood or become irritable more easily.

There may sometimes be other side-effects that are not listed above. If you notice anything unusual and are concerned, contact your doctor. You can report any suspected side-effects to a UK safety scheme at www.mhra.gov.uk/yellowcard

Can other medicines be given at the same time as ethosuximide?

  • You can give your child medicines that contain paracetamol or ibuprofen, unless your doctor has told you not to.
  • Ethosuximide should not be taken with some medicines. Tell your doctor and pharmacist about any other medicines your child is taking before starting ethosuximide.
  • Check with your doctor or pharmacist before giving any other medicines to your child. This includes herbal and complementary medicines.

Epilepsy and pregnancy

  • Pregnancy presents a risk to both the mother with epilepsy and her unborn baby. If your daughter has sex, it is essential that she uses contraception to prevent pregnancy.
  • If your daughter thinks that she may be pregnant she should see her doctor as soon as possible but continue taking her medication in the meantime. 

Ethosuximide and pregnancy

  • The risk of ethosuximide causing harm to an unborn baby is low but your daughter must speak to her doctor before trying to conceive.
  • The oral contraceptive pill can be used safely by women or girls who are taking ethosuximide.

General advice about medicines for seizures

Do not suddenly stop giving any of these medicines to your child, as they may have a seizure. If you are worried, contact your doctor but carry on giving the medicine to your child as usual.

If your child seems to have more seizures than usual, contact your doctor or epilepsy nurse.

  • If your doctor decides to stop a particular medicine, they will discuss this with you. They will usually reduce the dose gradually.

Do not change the dose of any drug without talking to your doctor first.

  • It is best that your child always has the same brand of each medicine, as there may be differences between brands. Keep a record of which medicines your child has.
  • Try to give medicines at about the same time(s) every day, to help you remember.
  • If you are not sure a medicine is working, contact your doctor but continue to give the medicine as usual in the meantime. Do not give extra doses, as you may do harm.
  • Only give the medicine(s) to your child. Never give them to anyone else, even if their condition appears to be the same, as this could do harm.

If you think someone else may have taken the medicine by accident, contact your doctor straight away.

  • Make sure that you always have enough medicine. Order a new prescription at least 2 weeks before you will run out.
  • Make sure that the medicines you have at home have not reached the ‘use by’ date on the packaging. Give old medicines to your pharmacist to dispose of.

Where I should keep this medicine?

  • Keep the medicine in a cupboard, away from heat and direct sunlight. It does not need to be kept in the fridge.
  • Make sure that children cannot see or reach the medicine.
  • Keep the medicine in the container it came in.

Who to contact for more information

Your doctor, pharmacist or nurse will be able to give you more information about ethosuximide and about other medicines used to treat epilepsy.

You can also get useful information from: 
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