Who has experience taking Dilantin?

I have recently diagnosed with epilepsy, and was put on Dilantin to control the seizures (I also take Lamictal, but that is for bipolar disorder). I've been taking Dilantin for just about a week or so, and I haven't had a seizure, but I was wondering if anybody has experienced long term side effects. If I take it on a long term basis, are there any side effects I should be aware of? At first I noticed a decrease in drive, but that has stabilized once I got better adjusted to the medication. Also, my memory has been totally blown since I started taking it. When somebody says something to me, I tend to immediately forget. Also, although I have a general idea of what I did yesterday, I can't remember the details. Forget about last week. That's just gone. Is this a common side effect, or should I discuss it with neurologist? I mean, I will discuss it with her at my next appointment, but in the meantime I was just hoping somebody could give me some pointer.