Seizure Medication
Seizure medications — a plain-English overview
The most commonly prescribed anti-seizure drugs for dogs and cats — what they do, how they work, and what questions to ask your vet.
When your vet recommends starting your pet on anti-seizure medication, it can feel overwhelming — especially when the drug names are unfamiliar. This guide explains the most commonly used medications in plain language so you can have a more informed conversation with your veterinary team. It is not a guide to choosing or dosing medication — that decision belongs entirely to your vet.
When does treatment typically start?
Not every pet with epilepsy requires medication immediately. According to IVETF treatment guidelines, veterinarians typically consider starting anti-seizure medication when seizures are frequent (more than one per month), severe, cluster in nature, or when there is status epilepticus. The decision is individualized and considers the pet's overall health, seizure type, and owner circumstances.
Phenobarbital — the most widely used first-line drug
Phenobarbital is an anticonvulsant that works by reducing abnormal electrical activity in the brain. It is the most extensively studied and widely used anti-seizure drug in veterinary neurology. Published studies suggest many dogs experience meaningful seizure reduction with phenobarbital treatment. It is given orally twice daily and requires regular blood monitoring to check drug levels and liver function.
Potassium bromide
Potassium bromide may improve seizure control in some dogs that do not respond adequately to phenobarbital alone. It is often used as an add-on therapy. It takes several months to reach stable blood levels and requires blood monitoring. It is generally not recommended for cats, as it can cause severe respiratory complications in feline patients.
Levetiracetam (Keppra)
Levetiracetam is a newer anti-seizure drug with a different mechanism of action. It is increasingly used in veterinary neurology — both as an add-on to phenobarbital and as a stand-alone agent. It is available in standard and extended-release formulations. It is generally considered well tolerated in many veterinary patients, though it requires more frequent dosing.
- How long before we expect to see this medication working?
- What side effects should I watch for, especially in the first few weeks?
- What blood tests are needed, and how often?
- What do I do if my pet has a seizure while on this medication?
- What would make you change or add a medication?
Abruptly stopping anti-seizure medication can trigger severe withdrawal seizures — including status epilepticus. If you have concerns about your pet's medication, contact your veterinarian before making any changes. This applies even if your pet appears to be seizure-free.
- Bhatti SFM, et al. International veterinary epilepsy task force consensus proposal: medical treatment of canine epilepsy in Europe. BMC Veterinary Research. 2015;11:176. doi.org/10.1186/s12917-015-0464-z
- Podell M, et al. 2015 ACVIM small animal consensus statement on seizure management in dogs. Journal of Veterinary Internal Medicine. 2016;30(2):477–490. doi.org/10.1111/jvim.13841
- Hamers MFN, et al. Quality of life in dogs with idiopathic epilepsy and their owners with an emphasis on breed. Frontiers in Veterinary Science. 2023;9:1107315. doi.org/10.3389/fvets.2022.1107315
See whether the medication is working
Track medication, side effects, and seizures together.
Vets judge a medication by seizure frequency over time — and by the side effects this guide tells you to watch for. The Pet Seizure Log gives you one place to record doses, timing, side effects, and seizures, so when your vet asks "is it working?" you have the record to answer instead of a guess.
Explore the Pet Seizure Log →Help advance pet seizure research
Your tracking data could contribute to better outcomes for every pet with epilepsy.