I’m probably not understanding the question, and I don’t understand epilepsy treatment. But why would it be illegal for you to have some pills in supply?
I simply forget to take mine sometimes, so I’m always ahead; and my pharmacy fills prescriptions automatically if there are refills left, and often does it long before I need the refill.
I have pills I’ve had for a few years that I don’t take anymore, I just haven’t disposed of them yet. I can take them to a pharmacy, they will dispose of them.