I take venlafaxine and my armpits go through periods of dampness. Even with antiperspirant on. The only antiperspirant that keeps me dry most often is secret clinical strength, and men's old spice (for some weird reason) Other antiperspirant for men doesn't work as well. I guess my armpits are picky. Haha!
Sweating is a common and bothersome adverse effect of treatment with antidepressants. Tricyclics and selective serotonin reuptake inhibitors (SSRIs) have both been clearly shown to cause sweating. Increased sweating has been reported with venlafaxine (Pierre and Guze, 2000) and bupropion (Feighner et al. 1984) as well.
Antidepressants, especially those that affect serotonin, can cause sweating. I doubt it would just be your feet, but who knows, these meds are weird. I have gotten the sweats from some meds, but for me it was all over sweats, not just the feet. Now, the callouses? No. Not the drug. Not sweating. What it can cause is fungal infections if it's constant, but you don't mention those. Buy any new shoes lately? New socks? If it is the drug, and it's working well for you, this probably isn't enough of a problem to stop taking it for. If it's not really working, then it might be. If you do decide to stop this drug, better soon after you start taking it than late. Don't quit suddenly. But again, if it's working try to find a way to live with this, as it's not the worst side effect you can get. Gotta be a lot better than being depressed. Try putting some corn starch on them. Try using moisture wicking socks or alternatively close to 100% cotton socks, assuming you can find them anymore. It's not easy. But it's easy to find wicking socks. When y0u can go barefoot. Let 'em breathe, in other words. All the best.