Levetiracetam vs Zonisamide: what's the difference?
How Levetiracetam and Zonisamide compare: what each is for, how it works, side effects and cost, side by side.
Last updated: October 2026 · 2 sources · see sources
Side by side
| Levetiracetam | Zonisamide | |
|---|---|---|
| Generic name | Levetiracetam | Zonisamide |
| Brand names | Keppra | Zonegran |
| For | Dogs and cats | Dogs and cats |
| Prescription | Prescription | Prescription |
| Used for | Treats seizures, often added to other seizure drugs in dogs. [1] | Treats epilepsy, on its own or added to other drugs. [2] |
| How it works | It changes how brain cells release signals, making seizures less likely. [1] | It blocks channels that let brain cells fire too quickly. [2] |
| Common side effects | Dogs: sleepiness, wobbliness. Cats: low appetite, drooling, sleepiness. [1] | Sedation, wobbliness, vomiting and low appetite. [2] |
| Use with care | Don't stop suddenly. Use caution with kidney disease. [1] | Not for pets allergic to sulfa drugs or with liver disease. [2] |
| Full guide | Levetiracetam (Keppra) guide | Zonisamide guide |
Key differences
On the basics they are alike: same kind of animal, same way to get them. The differences are in how they work and what else they cover, shown in the table above.
Which one is right for my pet?
That is a call for your vet. They weigh your pet's age, weight, other health problems, other medicines and what you can realistically give at home.
Switching from Levetiracetam to Zonisamide is common, but do it only with your vet's plan.
Common questions
What is the difference between Levetiracetam and Zonisamide?
Both are seizure medicines that can be used alone or added to others.
Is Levetiracetam better than Zonisamide?
Neither is better for every pet. Your vet chooses based on your pet's species, age, health history, other medicines and what you can manage at home.
Can my pet take Levetiracetam and Zonisamide together?
Only if your vet says so. Some medicines in the same family should not be combined, and others are often used together. Always check before adding or switching.
Do Levetiracetam and Zonisamide need a prescription?
Levetiracetam: Yes. It needs a prescription from a veterinarian. Zonisamide: Yes. It needs a prescription from a veterinarian.
Related
This page is general information for planning, not veterinary advice. Talk to your vet about your own pet.