Epilepsy and seizures in dogs
Epilepsy in dogs: causes, treatment, and the role of adjunct options like CBD oil. Evidence-based explanation for dog owners.
Short & honest
Epilepsy is the most common neurological disorder in dogs. Conventional medication (phenobarbital, potassium bromide) is the cornerstone of treatment — strong evidence (grade A). CBD oil as an adjunct is promising but insufficiently studied to replace medication.
Veterinary review not yet completed
This page is awaiting review by a registered veterinary surgeon. Until then, treat the text as education based on the sources listed — not as a verified veterinary judgement.
What is epilepsy in dogs?
Epilepsy is a brain disease characterised by recurring, unprovoked seizures. It is the most common neurological disorder in dogs, with a prevalence of approximately 0.82% in first-line practice [3]. In clinical hospital populations, this is higher (1–2%). Male dogs and dogs aged 3–6 years are at increased risk [3].
Causes
The International Veterinary Epilepsy Task Force distinguishes three classes [2]:
- Idiopathic epilepsy — genetic/hereditary, most common. No identifiable brain damage.
- Structural epilepsy — demonstrable brain pathology due to brain tumour, inflammation or injury.
- Epilepsy of unknown cause — classification not possible based on available diagnostics.
Breeds with an increased predisposition include Labrador Retriever, Border Collie, Belgian Shepherd, Beagle and Australian Shepherd [3]. In Border Collies, 94% involve cluster seizures.
Conventional treatment
The ACVIM advises starting medication upon two or more seizures within six months, in cases of status epilepticus, cluster seizures, demonstrable brain pathology or prolonged postictal recovery [1].
First-line medication:
| Agent | Evidence | Effectiveness |
|---|---|---|
| Phenobarbital | Level I, Grade A [1] | 60–93% at therapeutic levels |
| Potassium bromide | Level I, Grade B [1] | Effective as mono- or combination therapy |
| Imepitoin | Alternative [1] | More favourable adverse effect profile |
Status epilepticus and cluster seizures are emergencies: treatment with diazepam (rectal or intravenous) followed by intravenous phenobarbital, in accordance with the ACVIM 2024 consensus [5].
Additional options
CBD oil
One randomised, double-blind, controlled study (JAVMA 2019, n=26) investigated CBD oil as an adjunct to existing medication in dogs with therapy-resistant idiopathic epilepsy [4]. In 89% of treated dogs, seizure frequency decreased significantly, with a dose correlation.
What this means in practice:
- The evidence is promising but limited — one small study is insufficient for a broad recommendation.
- CBD oil was investigated exclusively as an adjunct to conventional medication, not as a replacement.
- Conventional medication remains the leading treatment.
- Quality and composition of CBD products vary greatly; always discuss use with a veterinary surgeon.
Other additional agents
For other additional interventions in epilepsy in dogs — such as dietary adjustments, herbal supplements or acupuncture — there is currently insufficient scientific evidence available to make recommendations.
Additional is not the same as replacing
Epilepsy in dogs requires veterinary supervision and medicinal treatment in almost all cases. Additional options may be useful as an addition in certain dogs, but must never replace existing treatment without consultation with a veterinary surgeon. Uncontrolled epilepsy carries serious risks.
Why this verdict?
The evidence for epilepsy treatment in dogs is strong (grade A): multiple randomised controlled trials, large cohort studies (n=455,553), and two international consensus guidelines (ACVIM, IVETF) support both the epidemiology and the efficacy of standard medication. For adjunct options such as CBD oil, only one small RCT (n=26) exists, making that category of evidence weaker.
Interactions with medication
- CBD oil can affect blood levels of phenobarbital and other antiepileptics — use only under veterinary supervision
- Herbal supplements with nerve-stimulating effects (e.g. ginseng, guarana) may lower the seizure threshold
Legal status (Netherlands)
In the Netherlands, CBD products for animals fall under animal feed; medicinal cannabis for animals is available only on veterinary prescription. Quality control of over-the-counter CBD products is limited.
Sources
- [1] 2015 ACVIM Small Animal Consensus Statement on Seizure Management in Dogs. Journal of Veterinary Internal Medicine, 2016. Guideline doi:10.1111/jvim.13841
- [2] International veterinary epilepsy task force consensus report on epilepsy definition, classification and terminology in companion animals. BMC Veterinary Research, 2015. Guideline doi:10.1186/s12917-015-0461-2
- [3] Seizure occurrence in dogs under primary veterinary care in the UK: prevalence and risk factors. Journal of Veterinary Internal Medicine, 2018. Cohort study doi:10.1111/jvim.15290
- [4] Randomized blinded controlled clinical trial to assess the effect of oral cannabidiol administration in addition to conventional antiepileptic treatment on seizure frequency in dogs with intractable idiopathic epilepsy. Journal of the American Veterinary Medical Association, 2019. RCT doi:10.2460/javma.254.11.1301
- [5] ACVIM Consensus Statement on the management of status epilepticus and cluster seizures in dogs and cats. Journal of Veterinary Internal Medicine, 2024. Guideline doi:10.1111/jvim.16928