My Doctor started weaning me off of Effexor 2 weeks ago (so I can try Lexapro) The transition wasn't nearly as bad as I was afraid it would be but the last 4 hours I have been having tons of "brain zaps" or "brain shivers" every couple of minutes. It doesn't hurt it just feels weird. It's very unnerving. I don't like it at all. I'm really hoping this doesn't last long.