I have never had sweating with Effexor, in fact I have no side effects at all. It seems everyone is different and have different nside effects to drugs.
I have taken other anti depressants with horrible side effects, but Effexor really suits me.
I took effexor on and off for about five years, and experienced both the exccessive sweating (particularly in my legs, while sleeping), and the continued sweating after getting off the effexor. While it is highly unlikely that the sweating you are currently experiencing is posing any danger to your health, it is certainly a (sometimes debilitating) nuisance when trying to engage in day-to-day function. The issue seems to be due to effexors indirect long term effects on sympathetic feedback mechanisms that govern upregulation and downregulation of sympathetic function. SSNRIs were a bad idea from the get-go, but thats another topic. It is possible that while on the effexor you developed an anxiety disorder whose effects were masked or minimized by the effexor. Once off the effexor, the symptoms of the anxiety disorder were allowed to materialize. The so-called "enhanced" serotogenic activity of the effexor may have easily contributed to this new anxiety disorder. It is also possible that nicotinic and/or muscarinic acetylcholine receptor function was modified (semi-permanently). In any case, try taking diphenhydramine (Benadryl, 25mg) about two hours before you'd normally expect the sweating to be at its worst. If you have accidently created a preliminary serotonin syndrome, have your doctor prescribe .5mg /day of clonazepam twice daily (or higher if needed; or alprazolam .5mg - 1mg as needed daily if the clonazepam is too slow-acting, too suttle, or causes muscle aches. There is also a little-known "manual override" mode accessible by humans through meditation and biofeedback, but unless you have enormous amounts of free time, little to no daily obligations, and a bit of knowledge in neurology, microbiology and Human physiology, this mode isnt a realistic option. The good news: It is roughly 88 percent likely that the sweating will dissipate over time (less than 1 year) regardless. How aggressively you want to pursue stopping it is more a function of how badly it is interfering with the quality of your consciousness. Good luck and stay hydrated!
The sweating could be cause by the norepinephrine (noradrenaline) reuptake inhibition, therefore, Effexor can be very stimulating on some people and this is increasing your chance of excessive sweating. It is often reported as a side-effect and it is most likely due to a more active sympathetic nervous system. Disturbed sympathetic nervous system will do what it takes to maintain adequate homeostatic functions (like sweating) to maintain the body at a proper temperature.
M4