Learn about ethosuximide for epilepsy

  • November 28, 2023
  • 4
In this article
A woman taking her medication with water

Do you - or someone you care for - experience absence seizures? This is a type of epilepsy where you appear to ‘daydream’. Ethosuximide is one of the most effective medicines used to treat absence seizures in children and adults. 

When you start taking ethosuximide, you’ll likely have a lot of questions. Here’s an overview of the key things to know about this medicine. 

What is ethosuximide?

Ethosuximide is a medication that is used to treat absence seizures (which used to be called ‘petit mal’ seizures) in children and adults. An absence seizure is when you lose consciousness and stare blankly for a few seconds.

Ethosuximide has been used to treat absence seizures since the 1960s. It is usually taken as a capsule that you swallow whole, or as a liquid. You might know this medication as Zarontin, which is the ethosuximide brand name. 

Ethosuximide is generally viewed as an effective medicine for treating absence seizures. Studies showed that over half of people achieve seizure freedom when taking Zarontin, and others experience much lower numbers of seizures than before. 

Ethosuximide doesn’t help control other types of seizures (such as focal seizures or tonic clonic seizures). But if you have absence seizures and also take medicine for other seizure types, then your doctor might prescribe Zarontin to treat the absence seizures 

You, or a child you care for, will usually take Zarontin twice per day. Your doctor will start you on a low dose, and gradually increase the amount until your seizures are under control. You should follow your doctor’s instructions exactly when taking Zarontin. 

Keep learning: Introduction to juvenile absence epilepsy

How does ethosuximide work?

We don’t know exactly how Zarontin works, but the medicine seems to ‘slow down’ how fast our brains send electrical signals. During an absence seizure, your brain experiences a sudden surge of electrical activity, but ethosuximide seems to make that less likely to happen. 

Ethosuximide side effects

One of the main advantages of ethosuximide is that it has relatively few side effects, and many people don’t experience any at all. Still, you should read the leaflet in the packaging so you’re aware of potential ethosuximide side effects.

Common, milder ethosuximide side effects

Here are some of the most common side effects: 

  • Feeling tired
  • Headaches
  • Feeling or being sick
  • Stomach pain
  • Constipation or diarrhea
  • Hiccups
  • Problems with balance or coordination
  • Confusion
  • Trouble sleeping (insomnia)

For most people, these side effects go away on their own after a couple of weeks. But if they continue to bother you, speak with your doctor. 

Rarer, more serious ethosuximide side effects

All known Zarontin side effects will be listed in the packaging, and you should read this so you’re aware of things to watch out for. Here are some of the more serious ethosuximide side effects:

  • Allergic reactions (usually starting as a rash)
  • Sore throats or sores in the mouth
  • A rash or itchy, blistering skin
  • Feeling depressed or anxious
  • Feeling aggressive
  • Hallucinations
  • Having suicidal thoughts

If you notice severe side effects, seek medical advice immediately.  

Suggested: Overview of seizure medications side effects

Ethosuximide long-term side effects

You may have heard that some anti-seizure medication can have long-term side effects - particularly around bone density. However, Zarontin does not appear to affect bone density. When you take ethosuximide, your doctor may occasionally order blood tests to check your general health. 

Epilepsy medication: Overview of the 7 most common medicines

Get reminders to take ethosuximide

Between school, work and other activities, it’s easy to forget to take your Zarontin - but this can increase your risk of having a seizure. And that’s where Epsy helps. You can use the app to set reminders to take your ethosuximide, as well as recording any seizures you have, or writing down side effects. Try Epsy today!

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