For me the worst were the nightmares. The vivid nightmares that I had caused so much anxiety when I would wake up feeling very thirsty.
Another problem I had was that I suffered from migraines. Effexor XR should not be taken when you take Maxalt, which is something I take for migraines. And my doctor didn't tell me. So I actually had to go to the hospital when I almost fainted from the mix.