Phenobarbital vs Levetiracetam: what's the difference?
How Phenobarbital and Levetiracetam 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
| Phenobarbital | Levetiracetam | |
|---|---|---|
| Generic name | Phenobarbital | Levetiracetam |
| Brand names | Luminal | Keppra |
| For | Dogs and cats | Dogs and cats |
| Prescription | Prescription | Prescription |
| Used for | A long-used first-choice drug for epilepsy in dogs and cats. [1] | Treats seizures, often added to other seizure drugs in dogs. [2] |
| How it works | A barbiturate that calms overactive brain signals. [1] | It changes how brain cells release signals, making seizures less likely. [2] |
| Common side effects | Sleepiness and wobbliness at first; more thirst, urination and appetite; raised liver values. [1] | Dogs: sleepiness, wobbliness. Cats: low appetite, drooling, sleepiness. [2] |
| Use with care | Liver checks and blood levels are needed. A controlled substance. Never stop suddenly. [1] | Don't stop suddenly. Use caution with kidney disease. [2] |
| Full guide | Phenobarbital guide | Levetiracetam (Keppra) 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 Phenobarbital to Levetiracetam is common, but do it only with your vet's plan.
Common questions
What is the difference between Phenobarbital and Levetiracetam?
Both treat seizures. Phenobarbital is the long-used first choice; levetiracetam is often added to other seizure drugs.
Is Phenobarbital better than Levetiracetam?
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 Phenobarbital and Levetiracetam 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 Phenobarbital and Levetiracetam need a prescription?
Phenobarbital: Yes. It needs a prescription from a veterinarian. Levetiracetam: 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.