I'm on Wellbutrin and Effexor and also have issues with excessive sweating. I've mostly cured my night sweats by splitting my Effexor dose to 75mg twice daily
and making sure I take my doses at the same times (eg: 8:30am--W 150mg, E 75mg and 8:30pm--W 150mg, E 75mg). My doctor thought there were two reasons for the sweating; 1. he thought night sweats were caused by withdrawal as the time for my next dose approached and making sure to take them at the same times has helped a lot (unless I take a sleeping pill; then I wake up soaked

) and 2. he thinks I might be under medicated and the sweating during the day is illness related. I noticed that it is worse when I have any kind of emotional turmoil (busy at work, getting upset b/c I made a big mistake, etc) and I guess that really can't be helped. He wanted me to increase my Effexor dose and I'm still considering it. I did start taking 150mg in the morning and 37.5mg in the evening, but I felt worse and went back to 75mg twice daily. If I give the increase another go I'm going to take 75mg and 37.5mg twice daily. It seems to work better for me if split into two equal doses.