mvpofpain1,
I've also been a long time sufferer of migraines. I've been on a number of preventative meds including Topamax - which has been my longest and most effective. At my highest, I was at 1200mg per day (which my dr did not like but kept me only for a short time) I am currently at 600mg per day (2 200mg in am and 1 200mg in pm) and this seems to work well. We have tried dropping below this but the frequency and intensity of the migraines increases. We also do nerve injections which are not as long lived as Botox, usually up to six months (Botox when applied multiple times lasts longer) but are covered under my insurance. I DO NOT claim to be an expert by any means, this is just my experience, if it helps you or I can answer any further questions for you please feel free to contact me. You are not alone in this fight.