Hi Hoobinkz,
I was on the medicine roller coaster, now i feel like i have one that has the least side effects for me. Sometimes combinations of medicine need to be taken. I've never been on Tegrotol, but i know keppra has some issues with some people. I for one had issues with it. Just take it slow and see how it affects you. If you don't feel right or notice thing are not working well on one med, then ask the doc to change it.
What is the reason you are switching meds? All i have to say is thank God we have a wide selection of medications. Although i don't recommend switching if one has worked well for a long time, because who knows if the newer med is better or worse. Only one way to find out though.