Pet Illnesses

Epilepsy in Dogs

What is Epilepsy?

Epilepsy is a periodic disease which is characterised by seizures (convulsions) with partial or complete loss of consciousness. Idiopathic epilepsy (of unknown cause) is the most common type seen in pets.

What are the signs?

Attacks usually commence without any warning, the pet falling to the ground, then undergoing a series of muscular jerks. There is extension (stiffening) of the limbs, followed by paddling and chewing movements. The eyes are fixed and staring. Loss of control can result in salivation and passing of urine and faeces. During an attack a pet should be left alone as they cannot swallow their tongue.
Following an attack, the pet gets up, looks around in a dazed manner and may run away with no idea of where it is going.
Attacks may occur frequently or infrequently. Milder seizures, with the pet remaining conscious, may sometimes occur.

Which pets are affected?

Although it can be seen in all aged animals, idiopathic epilepsy is generally seen in pets between 1 and 5 years of age. Seizures in pets outside this age group are more commonly caused by some other disease process. Although it is seen all breeds of pets, there is an increased occurrence in certain breeds e.g. German shepherds, Beagles.

What causes Epilepsy?

The cause of idiopathic epilepsy is still unknown although it is likely to be a genetic problem in some breeds. A thorough veterinary examination including some pathology tests are required to help distinguish idiopathic epilepsy from other causes of seizures, such as nervous signs due to lead poisoning.

Can seizure episodes be prevented?

As the cause of idiopathic epilepsy is still unknown, there is no specific treatment to remove the cause of the seizure. However, medication with appropriate drugs can either prevent, or considerably reduce, the frequency and intensity of the seizures, enabling the pet to lead a normal life. Although a number of drugs have been used to prevent seizures, the initial drug of choice is Phenobarbitone. This is considered the safest and most effective preventative therapy.

Once Phenobarbitone therapy is commenced, seizures may still occur for up to 2 weeks until the required levels of the mediation are reached in the blood and brain. Also, according to the animal’s response, the dose rate may have to be adjusted during the course of the treatment. pets typically require medication for the duration of their life.

In most epileptic pets, control of seizures with Phenobarbitone is usually successful. However, some pets develop an unresponsive form in which even very high doses of phenobarbitone are ineffective. When this occurs, control may be achieved by the addition of a second drug, Potassium Bromide which can be used in conjunction with Phenobarbitone. The combination of these two medications results in effective control and prevention of seizures in most pets. As with Phenobarbitone, it can take several weeks before Potassium Bromide has an optimum effect.

How can success of treatment be monitored?

To assist in monitoring the success of treatment, the frequency of seizures should be recorded on a calendar. Because one of the most common causes of poor control is too low a dose of the medication (due to large differences in response between pets), we may suggest monitoring the levels of the medication in the blood. The dose rate of the medication can then be adjusted according to blood levels and degree of seizure control.

Are there any side effects with medication?

The main side effect with these medications used to effectively control epilepsy are sedation and unsteadiness. This is generally seen at the commencement of treatment and usually disappears after a short period as the pet adapts to the medication. In a very small percentage of cases, some effects on the liver can occur and it is therefore recommended that on occasions, blood tests to assess liver function are undertaken.


Although epilepsy is a frightening disorder to both to the pet and the owner, treating with Phenobarbitone (and possibly in combination with Potassium Bromide) provides effective control in most cases. This allows the pet to lead a full and active life when maintained on the medication.