An anti-epileptic for absence seizures
Ethosuximide
An anti-epileptic medicine used as a first-line treatment for absence seizures, mostly in children.
What is Ethosuximide?
Ethosuximide is an anti-epileptic medicine used mainly to treat absence seizures (sometimes called petit mal), brief 'blank' episodes that often start in childhood. It is usually one of the first choices for this particular type of seizure but does not control other seizure types. It commonly causes stomach upset, nausea and drowsiness, especially when first started. Blood-count checks are sometimes advised because, rarely, it can affect the blood, and it should never be stopped suddenly.
Education and reference only. This is a plain-language guide to Ethosuximide — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Ethosuximide is a medicine that calms over-active electrical activity in the brain to prevent absence seizures, the short staring or 'switching off' spells most often seen in children. It is taken regularly, every day, as a capsule or liquid, to keep seizures under control. It works specifically against absence seizures and is not effective for other seizure types, so it is sometimes used alongside another anti-epileptic if a person has more than one type.
How it works
Ethosuximide is thought to work by quietening a particular type of electrical channel in the brain cells involved in generating absence seizures. By dampening this rhythm, it reduces the brief lapses of awareness that make up an absence seizure. Because it targets this specific mechanism, it works well for absence seizures but does not help most other seizure types, which are handled by different medicines.
Company & origin
Originated / developed by: Generic (long-established).
A long-established anti-epileptic used in the UK as a first-line treatment for absence (petit mal) seizures, mainly in children.
What it treats
Conditions Ethosuximide is used for
Practical use
How to take Ethosuximide
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it every day as prescribed, at the same times, to keep a steady level in your body.
- Take it with or after food if it upsets your stomach, which is common when starting.
- If you are given the liquid, measure it carefully with the spoon or syringe provided.
- Do not stop it suddenly, even if you feel well, as this can bring on seizures; any change is made gradually.
- Tell your prescriber straight away if you get a sore throat, fever, mouth ulcers or unusual bruising.
- If you miss a dose, take it when you remember unless it is nearly time for the next one; do not double up.
Weighing it up
Advantages & disadvantages of Ethosuximide
Advantages
- An effective, well-established first-line choice specifically for absence seizures.
- Available as a capsule and a liquid, which suits children who cannot swallow capsules.
- Has a long track record of use, so its effects and cautions are well understood.
Disadvantages
- Commonly causes stomach upset, nausea and drowsiness, especially at first.
- Only works for absence seizures, so another medicine is needed if other seizure types are present.
- Rarely affects the blood cells, which may mean blood tests and watching for infection or bruising.
Practical use
Good to know
Ethosuximide is taken every day to prevent seizures, not to stop one once it has started. Stomach upset, nausea, loss of appetite and drowsiness are common early on and often settle; taking it with food can help. It should never be stopped abruptly, as this can trigger seizures; any change is made gradually under medical guidance. Rarely it can affect the blood cells, so you may be asked to report signs such as sore throat, fever, mouth ulcers, unusual bruising or bleeding, and blood tests are sometimes done. As with all anti-epileptics, tell your prescriber promptly about new or worsening low mood or thoughts of self-harm.
Who should not take it / use with caution
- People who have had a serious allergic reaction to ethosuximide should not take it.
- It is used with extra care, and monitoring, in people with liver or kidney problems.
- It is used cautiously in anyone with a history of blood disorders or significant mood problems.
Monitoring
- Reviewing how well seizures are controlled and whether side effects are tolerable.
- Blood tests are sometimes used to check blood cells, and occasionally the medicine level.
- Watching for new or worsening low mood, and for signs of infection or bruising.
Side effects
- Nausea, stomach upset, loss of appetite, drowsiness and hiccups are common, particularly early on.
- Headache, dizziness or tiredness in some people.
- Rarely, blood problems (with sore throat, fever or bruising) or skin reactions that need prompt checking.
Key interactions
- Other anti-epileptic medicines can raise or lower ethosuximide levels, so doses may need adjusting.
- Medicines that cause drowsiness, including alcohol, can add to its sedating effect.
- Tell your prescriber about all your medicines, as changes can affect seizure control.
Available as: Capsules and oral liquid taken by mouth.
Answers
Ethosuximide: frequently asked questions
What type of seizures is ethosuximide for?
It is used mainly for absence seizures (petit mal), the brief 'blank' or staring spells that often start in childhood; it does not treat most other seizure types.
Can I stop it once seizures settle?
Do not stop it suddenly, as this can trigger seizures; any change must be made gradually under your prescriber's guidance.
Why might I need blood tests?
Rarely it can affect the blood cells, so blood tests are sometimes done and you should report a sore throat, fever, mouth ulcers or unusual bruising.
Should I take it with food?
Taking it with or after food often reduces the nausea and stomach upset that are common when starting it.
What if I miss a dose?
Take it when you remember unless it is almost time for the next dose; in that case skip the missed one and never take a double dose.
Authoritative sources
- BNF
- NICE CKS
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