I was switched from Effexor 225mg to Pristiq 50mg 3 weeks ago. I weaned off the Effexor while taking the Pristiq but occasionally took one of both or two Pristiqs to help with the migraines and fuzziness (which it did). I ran out of Pristiq which should arrive in a few days so NEED to take Effexor again to maintain and alleviate the fuzzy mind and crying until I get my Pristiq and it starts working.