I have had a constant migraine for the past 2 & 1/2 years that does not want to go away?

[joseph]

I have had a constant migraine for the past 2 and 1/2 years and does not want to go away. I have seen several doctors and have had several test run and nothing comes up. My doctors first thought it was being caused by High Blood Pressure but my blood pressure is under control. I have tried and failed several migraine medications ie: Axert, Zomig, Trexamet, Maxalt, Relpax, and Imitrex. My neurologist just suggested taking Namenda, I have been trying to look for some information online and talk to several Pharmacists but I have not been able to find anything except 1 article that was published back in 2007. I was wondering if anyone else has had this issue and has taken Namenda for it. Any information I can get would be greatly appreciated thank you