You really need both peak [ie 2-3 hours after a dose] and trough [ie just before the next due dose] levels to find out whether a dog is getting the correct Phenobarbitone [Epiphen] therapeutic level required.

I have every confidence in my Vet, and I'm sure that he knows what he is doing with Henry's treatment.

I am very pleased for you. I just wonder why, if you have every confidence in your Vet, you have been asking for advice here. That is all. As you no longer wish for advice I will leave this thread, but with one last comment. If your Vet considers a Pb trough level of 17.5 as being "well within the therapeutic range" - which is 15-40 and you are happy with that, then I wish you, and Henry, every good luck for the future.

I was asking about the side effects of any medication that may have been prescribed. Obviously, Epiphen alone is not controlling Henry's seizures and I was concerned about any adjunct to the Epiphen. Seemingly, potassium bromide has been well tolerated by the dogs of other posters.

I have been grateful for your input, but I also have confidence in my Vet.