I have been on effexor er since 1999. worked well. Bad side effects when taking little to late and would actually start going through withdraw almost immediately. Now there are 2 brands of the generic vanflaxine. When switched from one generic to the i have serious side effect. Almost like i have just discontinued taking it, I get way down and depressed, wanna sleep, dizzy, cant hold a conversation, It feels like a bad flu. Dr. said not posible made the same. so oi am crazy?