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What is a tonic-clonic seizure and how should it be managed in first aid?

A tonic-clonic seizure is the most widely recognised type of epileptic seizure and is caused by abnormal electrical activity affecting both sides of the brain. It usually has two phases: the tonic phase, where muscles suddenly stiffen and the person may cry out as air is forced from the lungs, and the clonic phase, where the body experiences rhythmic jerking movements. Throughout the seizure, the person is unconscious and unaware of their surroundings.

Breathing may become irregular or briefly stop during the tonic phase, and the person may lose bladder or bowel control. The seizure typically lasts 1–3 minutes. After it ends, the person often feels very tired, confused, or may have a headache—this is called the postictal phase.

In a first aid situation, your priority is to keep the person safe and comfortable until the seizure ends naturally. Move any dangerous objects away, cushion their head, and time the seizure. Never attempt to restrain them or place anything in their mouth, as this can cause injury.

Call 000 if:

  • The seizure lasts more than 5 minutes.
  • Another seizure follows immediately.
  • The person has trouble breathing afterwards.
  • The person is injured, pregnant, has diabetes, or this is their first seizure.

Once the seizure is over, roll the person into the recovery position to keep their airway clear, and stay with them until they are fully alert. Prompt, calm first aid can reduce the risk of injury and help the person recover safely.

A tonic-clonic seizure causes muscle stiffening, jerking, and loss of consciousness, needing calm, protective first aid.

Signs and symptoms:

  • Sudden collapse and loss of consciousness

  • Muscle stiffening followed by jerking movements

  • Irregular breathing or brief breathing stop

  • Loss of bladder or bowel control

  • Confusion or fatigue after the seizure

First aid for tonic-clonic seizures:

  • Stay with the person and remain calm.

  • Protect them from injury by moving hazards away.

  • Place something soft under their head.

  • Do not restrain or put anything in their mouth.

  • After the seizure, place them in the recovery position and monitor breathing.

Takeaway to Remember

A tonic-clonic seizure is a type of generalised epileptic seizure involving muscle stiffening (tonic phase) followed by rhythmic jerking (clonic phase). It often causes loss of consciousness and requires safety-focused first aid.