A young black boy in a wheelchair with a protective helmet against a blue backdrop wearing a white t-shirt

Atonic seizures

Back to generalised seizures

What is an atonic seizure?

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

It’s like someone hits the off switch on your muscles — you just drop, fast and without warning. It only lasts for seconds. 

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

Atonic is the opposite of tonic. During an atonic seizure muscle tone is reduced, as opposed to going rigid like in a tonic or tonic-clonic seizure. People who have other seizure types, such as tonic or myoclonic seizures, may also have atonic seizures.   

What do atonic seizures look like?

Your muscle tone reducing can cause you to suddenly flop forward and, if you are standing, fall to the ground. This is sometimes called a ‘drop attack’. 

In babies, atonic seizures most often appear as a ‘head drop’.   

What do atonic seizures feel like?

During an atonic seizure, you may lose consciousness for a short time, but you usually recover quickly. 

If you are at risk of atonic seizures, or they happen often, you may need to wear protective headgear, such as a helmet. This is because of your risk of injury from falling or losing consciousness.  

 

How to help someone who is having an atonic seizure

You told us what really helps when you're having a seizure, and we listened. This guidance is shaped by a powerful mix of lived experience and clinically informed expert advice, coming together to help others know what to do.

Even though these seizures only last a few seconds, someone having one still needs your help. 

To help someone who is having an atonic seizure, follow these steps: 

  • Don’t try to catch them but do guide them down gently.  
  • Stay with them and make sure they’re safe.  
  • Be calm and reassure them.  
  • Make sure they’re okay and haven’t hurt themself.  
  • Listen to how they want to be supported.
    • How they feel after the seizure can be different each time. They might be a bit confused, or they might feel okay.  

Call an ambulance if they’ve 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 atonic seizures

If you have atonic 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 be offered, 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