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Tonic seizures

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What is a tonic seizure?

Tonic seizures can be generalised(affecting both sides of the brain from the start) or focal (they start in one side of the brain). 

Your body suddenly goes stiff. You can’t move, and you’re totally unaware it’s happening. It’s like you’re frozen.  

 

Sometimes you might stretch your neck, raise your arms, cry out or your eyes roll back.  

- Description from young people with epilepsy in the Youth Voice Network

The name ‘tonic’ means an ‘increase in tone or tightness’ of the muscles. 

 

What do tonic seizures look like?

During a tonic seizure, the muscles in your chest, arms and legs may contract rapidly, causing your arms, legs and body to become stiff (rigid). Your back may also arch and your breathing may change. Changes to your breathing, may mean that your skin colour changes slightly, for example the skin around the mouth may look blue. This is because your lungs are getting less oxygen.  

Seeing someone have a seizure can be very distressing but remember that they often do not last for very long. Tonic seizures are generally short (less than a minute) and the person will usually recover from them quickly.   

What do tonic seizures feel like?

Tonic seizures can come on suddenly—one moment everything’s fine, the next your body goes stiff, and you can’t move or speak. If you're standing, you're likely fall.  

You are not aware it’s happening, but others might notice your neck stretching, arms lifting, or eyes rolling back. Sometimes there’s a cry.

Once the seizure has stopped, you regain consciousness, and your muscle tone goes back to normal.  

How to help someone who is having a tonic seizure

To help someone who is having a tonic seizure, follow these steps: 

  • Time how long their seizures lasts. 
  • Stay with them and make sure they’re safe. 
    • Move any hazards, like furniture, out of the way.
    • Don’t move them unless it’s absolutely necessary, for example, if they are close to a hazard that cannot be moved, like an open fire, roads or open water. 
  • Be calm and reassure them, even if you think they can't hear you.  This isn’t always easy, but it’s very important, especially when the person is recovering from the seizure and looking to you for reassurance. 
  • Make sure they’re okay and haven’t hurt themself.
    • Don’t let strangers crowd around or film them on their phone.
    • Please don’t put anything in their mouth.
    • Don’t hold them down or try to bring them round. 
  • Listen to how they want to be supported.
    • How they feel after the seizure can be different each time, they might be weak, confused and upset. Or they might feel okay.

Call an ambulance if:

  • the seizure lasts for more than five minutes
  • they have one seizure after another before they have recovered, or
  • they have seriously injured themself.

The person may have an emergency management or care plan. If they do, you should follow the instructions in their plan. Their plan may include giving them their prescribed emergency medication, but do not administer emergency medication unless you are trained to do so. If you have to call 999, stay on the line and follow the guidance of the call handler. 

Find out more about emergency medication

Treating tonic seizures

If you have tonic seizures, your doctor may suggest you start by trying a single med. For example, lamotrigine or sodium valproate. If the one you try does not work or you have side effects, you can try the other med either on its own or as an add-on. 

If both of these meds do not work, your doctor may suggest something else. Like different meds or the ketogenic diet. 

If you’d like to know more about what meds you might have, talk to your doctor. Or go to the NICE website to read the most up-to-date guidelines. 

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Last reviewed July 2025.

Next review due July 2028.

If you would like to find out more about how we produce our information, or the sources of evidence we use, please contact us at healthinfo@youngepilepsy.org.uk