The side effects of each of these medications varies so much that it is hard to predict but when sexual side effects occur it is very common to switch in exactly this way.
The first two medications are usually used before wellbutrin because they are generally considered more potent.
I was switched to Wellbutrin..... which again didn't seem to quite do the trick..... I didn't notice any real change in libido (I'm female though, side effects are likely different for men)
I just started taking effexor.... Don't know a thing about it really, only been taking it for a week, and don't notice a change......
Wish you and bf well.
Good luck
LG
Thank you very much.
Jeanette