Phenobarbital

Molecular Formula: C12H12N2O3
CAS Number: 50-06-6
Appearance: white crystalline powder or colorless crystals

Phenobarbital to Treat Dogs and Cats for Seizures. Phenobarbital is the medication that is most commonly used to treat seizures and epilepsy in dogs and cats. … Because it is a barbiturate, phenobarbital is a controlled drug and can only be obtained with a prescription from your pet’s veterinarian.