I'm a week into a cross taper from citalopram to Effexor XR, after another week I will drop the last of the citalopram and increase Effexor to 75mg. So I've been incredibly tired, a bit jittery/anxious, chills and low. So I guess after crossing to 75mg I will have a few more side effects but I read that 75mg Effexor is the same dosage as 20mg citalopram. So I'm wondering could 75mg as a dose still be effective for me since it's a different medication as I always only needed 20mg cit unless I had a depressive episode where I went up to 30mg. My psych doesn't think I'll need too high a dose but i can't even remember when I felt better after taking the citalopram at first as it was 12 years ago.

Can anyone inform me what is the difference in dosages between the two drugs?