I switch from lexapro (sexual sideffects) to effexor Xr(sexual sideffects gone now) on 1- 25 -13. With Effexor Xr I find my self drowsy no need for naps tho.It's been 16 days usally when does the drowniess ease up or leave. I took effexor before and I can't remeber how long I was drowsy.If effexor Xr made you drosy how long did it take to pass. I tryed it at night but still drosy in day. Do I need to give it a month or longer.