I have been taking Vimpat as a test medication for over three yrs. I also was taking Keppra, Topamax, and Dilantin. I was seizure free after about 10 months on the test Med. I am now off of Topamax, and have reduced my Keppra from 3000mg a day to 750mg a day. It works, and the biggest side affect for me was as a passenger in a car, I could not keep my eyes open for more than 10 minutes. I have now gotten used to the drug and no longer have that side effect. Even when I was able to drive again, I did still have the side affect while a passenger, but never when I was at the wheel. Good luck with this drug, it has been incredible for me.