Understanding Canine Epilepsy
Epilepsy is the most common neurological condition diagnosed in dogs, affecting an estimated 0.6 to 0.75 per cent of the canine population. It is defined as a brain disorder characterised by recurrent, unprovoked seizures — that is, seizures that occur without an identifiable immediate trigger such as a toxin or a sudden drop in blood sugar at that moment. Living with an epileptic dog is manageable for most families, but it requires understanding, preparation, and a strong partnership with your veterinary team.
Classification: The IVETF System
The International Veterinary Epilepsy Task Force (IVETF) developed a classification system that is now the accepted standard in veterinary neurology. Understanding where your dog's epilepsy sits within this framework helps clarify the diagnostic process and guides treatment.
- Idiopathic epilepsy: No identifiable underlying structural brain disease or other cause. This is genetic or presumed genetic in origin and is the most common type of epilepsy in dogs. It is a diagnosis of exclusion — other causes must be ruled out first.
- Structural epilepsy: Seizures caused by identifiable pathology within the brain, such as a tumour, inflammation (encephalitis), trauma, or a vascular event.
- Epilepsy of unknown cause: Seizures occur but no cause can be identified, though structural disease cannot be fully excluded either. This category acknowledges the limits of available diagnostics in some cases.
Types of Seizures
The IVETF also defines seizure types, and understanding these helps owners describe episodes accurately to their vet — which is invaluable for diagnosis and monitoring.
Generalised Seizures
Generalised seizures involve both hemispheres of the brain simultaneously. The most familiar form is the tonic-clonic seizure — sometimes called a grand mal — in which the dog loses consciousness, falls onto its side, exhibits rigid muscle contractions (tonic phase) followed by rhythmic paddling or jerking movements (clonic phase), and may urinate or defecate. Other generalised types include tonic (sustained rigidity), clonic (rhythmic jerking only), myoclonic (sudden muscle twitches), atonic (sudden loss of muscle tone causing collapse), and absence seizures (brief episodes of altered awareness without convulsions).
Focal Seizures
Focal seizures originate in one region or hemisphere of the brain. They may manifest as facial twitching, rhythmic blinking, chewing movements, fly-catching behaviour (snapping at invisible objects), sudden vocalisation, or repetitive limb movements. The dog may or may not lose consciousness. Focal seizures can progress to affect both hemispheres — described as focal to bilateral tonic-clonic — which can make them difficult to distinguish from generalised seizures if the focal onset is brief.
The Three Phases of a Seizure
Most seizures have three recognisable phases. The pre-ictal phase (or aura) occurs in the minutes or hours before the seizure itself. Dogs may appear anxious, restless, clingy, or unusually withdrawn. The ictal phase is the seizure itself — this is what most people recognise. The post-ictal phase follows the seizure and can last from minutes to several hours. During this time dogs may be confused, temporarily blind or deaf, exhausted, or very hungry. Post-ictal signs can be distressing to witness but are normal and will resolve.
Emergencies: When to Act Immediately
Two situations require urgent veterinary attention and should never be managed with a wait-and-see approach at home.
- Cluster seizures: Two or more seizures occurring within a 24-hour period. Contact your vet immediately.
- Status epilepticus: A single seizure lasting more than five minutes, or two or more seizures occurring without the dog fully regaining consciousness between them. This is a life-threatening emergency — call your vet immediately and, if you have been prescribed rectal or intranasal diazepam for home use, administer it now as directed.
Both situations require emergency intravenous anticonvulsant therapy. Prolonged or repeated seizure activity causes brain injury, hyperthermia, and metabolic disturbances that can be fatal without rapid intervention.
What to Do During a Seizure
Witnessing your dog having a seizure for the first time is frightening. Keep the following in mind. Do not try to restrain the dog — you may inadvertently be bitten and restraint does not help the dog. Do not place your hands near the dog's mouth under any circumstances. Dogs cannot swallow their tongue; this is a persistent myth that causes unnecessary harm to owners. Clear the immediate area of furniture, stairs, or hazards the dog could injure itself on. Dim the lights and reduce noise. Time the seizure from start to finish. Stay calm, and video the episode if safe to do so — footage is extraordinarily helpful for your vet. Comfort the dog gently during the post-ictal phase.
Diagnosis
Diagnosis begins with a full clinical and neurological examination. Routine blood tests, urinalysis, and bile acid testing help identify metabolic causes. MRI of the brain is the gold standard for detecting structural disease. Cerebrospinal fluid (CSF) analysis may follow MRI to investigate inflammatory or infectious causes. Electroencephalography (EEG) is rarely used in veterinary medicine. The age of the dog at the time of the first seizure is a useful clue: idiopathic epilepsy typically begins between one and five years of age. A first seizure in a dog under one year or over five years of age raises greater suspicion of structural or metabolic disease and warrants thorough investigation.
Breeds With High Prevalence of Idiopathic Epilepsy
Several breeds are known to have a significantly elevated prevalence of idiopathic epilepsy, including Border Collies, Labrador Retrievers, Belgian Shepherds (particularly the Belgian Tervuren), German Shepherd Dogs, Golden Retrievers, Irish Wolfhounds, Boxers and Beagles. Genetic research is ongoing in many of these breeds.
Treatment
The decision to start long-term anticonvulsant medication is typically made after a second seizure, or immediately following a first seizure that was a cluster event or status epilepticus. Several medications are available.
- Phenobarbital: The first-line treatment in the United Kingdom and widely regarded as the most effective single anticonvulsant for dogs. It is given twice daily and requires monitoring every six months — including liver enzyme levels and therapeutic drug monitoring — because it induces liver enzyme activity over time.
- Potassium bromide (KBr): Used as an adjunct to phenobarbital or occasionally as an alternative. It is slow to reach therapeutic levels (weeks) and can cause sedation and increased appetite. It must never be used in cats.
- Imepitoin (Pexion): Licensed specifically for canine idiopathic epilepsy in the European Union and United Kingdom. It has a favourable side effect profile and is a reasonable first-line option for milder cases, though it is generally considered less potent than phenobarbital.
- Levetiracetam and zonisamide: Used as add-on therapies in dogs whose seizures are not adequately controlled on first-line medication alone.
Monitoring and Quality of Life
Keeping a seizure diary is an essential part of managing epilepsy. Recording the date, time, duration, type, and recovery for each episode gives your vet the information needed to assess whether treatment is working and whether doses need adjusting. Several dedicated apps — including EpiPaws and PetPace — have been developed for this purpose. With appropriate medication, regular monitoring, and an informed owner, the majority of epileptic dogs live happy, comfortable, and largely normal lives.