WHOA NELLIE!!!! 
STOP THEM HORSES!!!
What ever you do, DO NOT, I REPEAT, DO NOT, mix AMERGE with Effexor. Very bad drug interaction. Cardio or Pulmonary arrest I believe. Can't really remember, but it was one of the fatal ones. This interaction can get missed when you go to different doctors or different pharmacies. That was my case, and luckily, father caught it in the knick of time. I've come to the opinion that you have to research your medications before you even have the scripts filled. Plus, if you don't see the same doctor each time, there is no continuity. Amerge is supposted to be used as an abortive medication, when a migraine attack first begins, not as a preventative, just like the other triptan family of drugs. Triptans should be used no more than twice a week, certainly not daily.
Topamax is the drup that is supposed to be the preventative. Most people max out at about 200mg. The slower you move up to 200mg, the less you feel the side effects. I, on the otherhand ,was already taking 200mg, and although my neurologist says that his regulart patients usually only take 100mg, he wanted to move me up to 400mg. My, aren't I a special girl. Well, I didn't want the side effects to last for months, so I just jumped from 200 to 400mg cold turkey. I would not recommend it to anyone. I'm pretty much a psychopath. Can't remember, anything, very vegatative. I wouldn't even think about driving right now. I do some hallucinating from time to time. If I'm asleep, I can make phone calls on my cell phone and wake up in the middle of them. It's just one big adventure.
I went into my Clinic for a migraine shot the other day. My Doctor wasn't available, after waiting three hours she asked one of the other doctors to see me. I wasnt' sleeping, which she thought was making thing worse (I agreed) so she gave me a prescription for Trazadone. Fine, then she decided that I was having too many migraine attacks (no brainer), so she whipped out her scripts pad and wrote me prescription. I couldn't see it, she wouldn't explain it to me, she didn't check my drug history for a listing of medications I've already tried. Nothing. She just said it would decrease the frequencey of my headaches. Geez, was I pissed. She also once before denied me a shot of Nubain because she though I had had one too recently and lied about the clinic changing policy on how often they could give those out. B***H. Well, I get the prescription home, and it's a (drumroll please........a calcium channel blocker). OK, I'm on the heavy side weight wise. However, I have very low blood pressure (the last time at the hospital was 90/62), I have low choelesterol, normal blood sugar. I'm very healthy for a really miserable person. Last time I had it checked warning on the bottle not to use on patients with low blood pressure. DUH 
Another bottle of pills in the trash.
I seem to have digressed. Hope that helps some. Let me know.
Leigh Ann 