Epilepsy with Tonic-clonic Seizures Causes and Treatment

Last updated by Peer reviewed by Dr Sarah Jarvis MBE, FRCGP
Last updated Meets Patient’s editorial guidelines

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At least 1 in 30 people in the UK develop epilepsy at some stage. It most commonly starts in infancy and in people over the age of 50. However, epilepsy can begin at any age. Seizures are well controlled by treatment for most people with epilepsy. There are different types of epilepsy. This leaflet is about epilepsy with tonic-clonic seizures.

A seizure is a short episode of symptoms caused by a burst of abnormal electrical activity in the brain. Typically, a seizure lasts from a few seconds to a few minutes. (Older words for seizures include convulsions and fits.)

If you have epilepsy, it means that you have had repeated seizures. If you have a single seizure, it does not necessarily mean that you have epilepsy. About 1 person in 10 has a seizure at some time in their life. It may be the only one that occurs. The definition of epilepsy is more than one seizure. The frequency of seizures in people with epilepsy varies.

For more information, see the separate leaflets called Epilepsy and Seizures and Types of Epilepsy and Seizures.

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A tonic-clonic seizure is the most common type of generalised seizure. The following gives a typical description of a tonic-clonic seizure:

Your body becomes rigid due to strong muscular contractions (the tonic part). You lose consciousness and fall. Your chest muscles contract and force air out of your mouth, often with a grunt. Your jaw muscles contract and you may bite your tongue. Saliva may escape from your mouth. Your bladder may contract and you may pass urine. This stiff or tonic phase soon passes into the clonic (shaking or convulsive) phase. This occurs when the muscles repeatedly contract and relax. Your whole body appears to shake. This may last from a few seconds to a few minutes.

When the tonic-clonic seizure has stopped, you gradually regain consciousness but you may be confused and dazed for a while. The time taken to recover varies. You may have some soreness due to the muscular contractions. You may have a headache and want to sleep after a seizure.

You may have some warning symptoms for a short while before a tonic-clonic seizure. This is called an aura. The aura can take various forms - for example, odd movements, odd sensations, or intense emotions. However, many people do not have auras, and a seizure commonly occurs without any warning.

A tonic-clonic seizure cannot be shortened or altered. However, a bystander can help in the following ways:

During a tonic-clonic seizure

  • Note the time.
  • Do - prevent crowds gathering round.
  • Do - place a cushion or some clothing under the person's head to prevent injury.
  • Do not - try to restrain the person. If there is a warning (aura) before a tonic-clonic seizure, it may be possible to guide the person to a safe place or cushion the expected fall to the ground. When the seizure starts, do not try to hold the person upright but let them lie down.
  • Do not - move the person unless they are in a dangerous place (for example, in a road or next to a fire). If possible, move dangerous objects away from the person.
  • Do not - place anything in the person's mouth or try to move their tongue.

Once the tonic-clonic seizure has stopped

  • Do - roll the person on to their side into the recovery position.
  • Do - check that breathing has resumed normally. It is normal for breathing to stop for a short while during the stiff (tonic) part of the seizure. The face will go pale or bluish. During the convulsive (clonic) part, breathing is irregular. After the tonic-clonic seizure is over, breathing returns to normal. If not, check there is nothing stopping breathing, such as food or false teeth. The recovery position helps saliva and anything in the mouth - such as food or sick (vomit) - to drain out of the mouth and not back into the throat.
  • Do - stay and talk to the person. Give reassurance until they are fully recovered. It may take a while for the person to wake up fully. Do not leave a person alone whilst they remain dazed or confused.
  • Do not - offer something to eat or drink until you are sure they are fully recovered.

Calling a doctor or an ambulance

There is usually no need to call a doctor or an ambulance, unless:

  • It is their first tonic-clonic seizure.
  • Injury has occurred which cannot be dealt with.
  • The tonic-clonic seizure does not stop after a few minutes. Status epilepticus is rare but means a seizure does not stop, or they keep recurring one after the other. This is an emergency and needs urgent treatment to stop the tonic-clonic seizure.
  • There is difficulty with breathing.

There are many different treatments for epilepsy and also medicines to help prevent people with epilepsy having seizures.

Sodium valproate is recommended as first choice treatment for generalised tonic-clonic seizures in

  • Boys and men.
  • Girls aged under 10 years who are unlikely to need treatment when they are old enough to have children.
  • Women who are unable to have children.

Editor's note

Dr Krishna Vakharia, 29th January 2024

The Medicines and Healthcare products Regulatory Agency (MHRA) has issued an update to the use of sodium valproate due to the risks associated with pregnancy and birth defects. These are:

  • Valproate should not be started in any new patients - both male and female- younger than 55 years of age.
  • If there is no other option for treatment or if pregnancy is not a risk, then two separate specialists must independently consider the drug and document why sodium valproate is appropriate.
  • If you are already on the medicine, at the next review, a second signature will be needed to continue with the medicine.
  • Do not stop taking valproate without advice from a specialist. This is because your condition may worsen without treatment.

However sodium valproate should be avoided in pregnancy and so lamotrigine or levetiracetam is used as first choice for women and girls able to have children. This also includes young girls who are likely to need treatment when they are old enough to have children. See also the separate leaflet called Epilepsy and Planning Pregnancy.

If sodium valproate does not control seizures and is stopped by your doctor, lamotrigine or levetiracetam should be offered as an alternative. If one of these is given and does not control seizures, the other one should be offered.

If your seizures are not completely controlled by the first medication, your doctor may recommend adding a second treatment to use in addition. The options will depend on your individual circumstances. They include clobazam, lamotrigine, levetiracetam, perampanel, topiramate or sodium valproate (except in women and girls able to have children).

If your epilepsy is still not controlled, your doctor may suggest switching your add-on treatment to brivaracetam, lacosamide, phenobarbitol, primidone or zonisamide.

For information about treatments and prevention, see the separate leaflet called Treatments for Epilepsy.

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Further reading and references