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Seizures in Dogs and Cats

Updated: Oct 24, 2022

What is a Seizure?

According to the Merriam-Webster medical dictionary a seizure is defined as = “an abnormal electrical discharge in the brain” (Webster, 2022). A seizure can also be referred to as a convulsion or fit.

Types of Seizures

When a seizure occurs several times, this is referred to as epilepsy, this can be that the seizure occurs once then not again for a prolonged period of time or there may be several consecutive seizures which is referred to as cluster seizures. A dog or cat can enter ‘status epilepticus’ when they have repeated seizures which last more than 5 minutes, this can become very serious, and you should seek immediate veterinary help. This is especially dangerous in cats! The above names are used to describe the frequency or duration of seizures but additional terms exist to describe the type of seizure. For example, a simple partial seizures is used to describe a seizure which only effects localised areas of the body without changes to consciousness, such as twitching of facial muscles. On the other hand, complex partial seizures also involve either loss of consciousness or impaired awareness. Finally, generalised seizures are used to describe a seizure which involves loss of consciousness with convulsions all over the body.

What Does a Seizure Look Like?

A seizure in dogs and cats can be divided up into 3 distinct phases:

1. Pre-ictal phase

This is the phase which occurs before the seizure where you may see changes in behaviour like nervousness, head turning, attention seeking.

2. Ictal phase

This is the seizure in itself, where you see twitching and tremors, shaking and spasms. They may lose consciousness and loose function of their bowels. It is very important to be aware that your pet will feel disorientated during the seizure, it is ok to make sure they won’t hit their heads on anything, or nothing is likely to fall on them and hurt them. But be aware that this disorientation may mean they bite you out of confusion.

3. Post-ictal phase

This is the phase after the seizure where the patient may be either sleepy and depressed or overly excited and wanting to eat and drink excessively.

What Causes a Seizure in Dogs and Cats?

There are many causes of seizures in dogs and cats:

  • A disease within the brain such as a tumour or secondary to damage to the brain from an injury (eg: secondary to head trauma in a road traffic accident).

  • Idiopathic epilepsy which is an inherited condition in dogs but uncommon in cats. Idiopathic can also be used to describe epilepsy when we do not know the cause.

  • They can also occur due to build up of toxins in the body if the kidneys or the liver are not working correctly to eliminate toxins as they usually do.

  • If your pet is prone to seizures, certain events such as excitement or feeding time can induce a seizure. This is because of the electrical imbalances this causes in the brain.

Seizures and epilepsy are less common in cats compared to dogs and are thought to be more related to brain injury or disease within the brain. In cats seizures are more likely to occur when they are going to sleep or waking up, compared to dogs.

What Should I do When my Pet is Seizuring and When Should I Call the Vet?

If you are concerned that your pet may have had or be having a seizure it is advisable to contact your vet. It is very important to not interfere with your pet when they are Seizuring since they may accidently bite you out of the confusion, it is best to ensure they are in a safe place, ie cannot hit their head on something. And just be there with them. If you are able to and it is safe to do so, taking a video of the incident may help your vet in diagnosing what is happening, and it will help guide their next steps.

What Will The Vet do Next?

If the vet believes that your pet’s condition is an emergency, then they will take your pet into the hospital to be stabilised straight away. This very much depends on how your pets presents to the vets and how long they have been Seizuring for. Your vet will use their best clinical judgement to determine if this is an emergency or not.

Some of the more general questions they may ask you include:

  • the age of your pet

  • when you first noticed the seizures and how old they were

  • are the seizures getting more intense or closer in time from one episode to the next?

  • what are they like before and after the seizures? How long does it take them to recover?

  • Medication history

  • Have they been exposed to any poisons or toxins? (Remember that certain flowers such as lilies can be toxic to cats)

Initially your vet will run blood and urine tests to determine if there are any possible underlying causes such as kidney or liver disease or any general underlying illnesses. More in-depth investigations may involve taking samples of the cerebrospinal fluid and MRI’s, which can be costly. Your vet should discuss the pros and cons of the advanced investigations and whether your pet should be put through those investigations and ultimately if this is affordable for you.

What Are The Treatment Options for Seizures in Dogs and Cats?

The treatment very much depends on the cause of the seizures and the frequency of them. Especially with cats, if the cause of the seizures is not determined but they have more than one seizure in a six to eight-week period then your vet may decide to start treatment.

If the cause of the seizures is due to toxin build up in the kidneys or liver then this should be addressed first, if the seizures continue then this may require further investigations. If there is a known brain trauma or tumour present, then there may not be much that can be done apart from controlling the seizures with medications.

If this is a one-off seizure with no obvious cause, then the vet may advise that you monitor your pet for any further episodes before deciding on any medications. It is important to consider that epilepsy is often a chronic disease which will progress with time and needs a lot of owner commitment in order to provide the best treatment and care for the patient. It is important to have this conversation with your vet and always consider the quality of life of your pet and whether you are able to take on this commitment fully.

The first line of treatment involves the use of an anti-epileptic medication such as Phenobarbital in dogs. There is no licenced medication for epilepsy in cats, however, phenobarbital is often used by vets. The levels of this medication in the blood system will need to be measured at regular intervals to check they are at the correct therapeutic level and managing to control the seizures. If this first line treatment does not work, then the dosage may be adjusted, or other medications may be added on.

Treatment side effects:

These are often seen in the first few weeks of treatment and should then settle down. Some of these signs can include = increased thirst and hunger, lethargy, panting, and many more depending on the medication prescribed. Always discuss with your vet what signs you should look out for and when to seek advice. However, if you are concerned always contact your vet!


1 Webster, M., 2022. Seizure. [online] Merriam-Webster. Available at: <> [Accessed 29 June 2022].

Vca. 2022. Seizures and Epilepsy in Cats | VCA Animal Hospital . [ONLINE] Available at:,and%20are%20termed%20idiopathic%20epilepsy.. [Accessed 29 June 2022].

Fitzpatrick Referrals. 2022. Epilepsy treatment for dogs and cats. [ONLINE] Available at: [Accessed 29 June 2022].


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