I haven't taken Trileptal, but I have taken Tegretol, and they are very similar.

Tegretol made me very tired and dizzy at first, but I adjusted to those side effects within about a week, I'd say. When I was on it I did think more slowly, but not less astutely. I think this experience is pretty common. A lot of folks here have taken Tegretol.

When on Tegretol, my neurologist did periodic blood tests to make sure everything was alright with my liver- there were never any problems. Trileptal is not as harsh on the liver as Tegretol. From wikipedia:

"Oxcarbazepine [Trileptal] is a structural derivative of carbamazepine [Tegretol], with a ketone in place of the carbon-carbon double bond on the dibenzazepine ring. This difference helps reduce the impact on the liver of metabolizing the drug, and also prevents the serious forms of anemia [lack of iron] or agranulocytosis [deficiency of some immune system cells] occasionally associated with carbamazepine."

If you are female (sorry, I don't know if you are or not) it is important to know the Trileptal can interfere with hormonal birth control, and also probably increases the risk of birth defects. When I was on Tegretol, the neurologist was adamant that I take extra Folic Acid to offset some of that risk.

In summary, you're probably going to feel tired and dizzy and a bit stupid for a while, but other than that, you'll probably be just fine. And even better, it will help the pain go away! Don't be afraid!