Sorry to hear about your pooch. I have a cat that has seizures and he has to be on phenobarb for them because he has status epilepticus which means when he goes into a seizure if he doesn't get injectible meds, he'll seize until he dies. He's done very well on his meds, we get his phenobarb level tested three times a year and he hasn't had a seizure in over 3 years.