NZ Formulary

Ethosuximide

eth-oh-sux-ih-mide

What does it do?

Ethosuximide is used to treat and prevent seizures.

Before you start

  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.

How should you take it?

Take ethosuximide regularly as directed. You can take it with or without food.
Capsule: Take with a glass of water.
Liquid: Measure carefully with an oral syringe or measuring spoon.

What if you forget a dose?

Take the missed dose as soon as possible and continue as directed.

Can you take other medicines?

Some medicines available without a prescription may react with ethosuximide including:

  • some antihistamines, such as chlorphenamine, hyoscine, meclozine and promethazine. These can be in medicines for allergies, nausea and colds.

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products (e.g. St John's wort, ginkgo) or recreational drugs (e.g. ecstasy).

What side effects might you notice?

Side EffectsRecommended action

Skin rash, skin peeling or blisters

Stop taking and see your doctor immediately

Suicidal thoughts

Reduced number of blood cells that fight infections or help your blood to clot - symptoms include: fever, chills, sore throat or generally feeling unwell, or easy or unusual bruising or bleeding

Tell your doctor immediately

Loss of co-ordination/walking or handwriting problems

Mood changes

Tell your doctor

Drowsiness, dizziness, headache

Loss of appetite, weight loss

Stomach upset

Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • Ethosuximide can impair your ability to do tasks such as driving or using machines. Alcohol makes this worse. Discuss your risk with your health professional. (search NZTA - Are you safe to drive?)
  • Do not stop taking ethosuximide without talking to your doctor first, unless you have a skin rash (see Side Effects).