Hmmm i was reading somewhere recently, may have been on this site, that somebody was tapering off Zoloft and going onto Prozac (may have been the other way round) and towards the end of the tapering it was advised that he/she go onto the other antidepressant so as to be taking both simultaneously, to avoid a time of possible relapse if the person quit one antidepressant and then had to wait at least two weeks for the next antidepressant to kick in. So if my memory is accurate, I think it is ok for both to be taken at once, but I have no idea what the reaction is.