I've saw a few post and some discussion about this, but my Oncologist suggested a low dose of Ritalin to ward off some of the fatigue and brain fog I was having from Firmagon and Zytiga.
I had been reluctant to take "another pill" that comes with more side effects...so I said not for me. I know the real cure for such is exercise, weights etc, but to tell you the truth, the fatigue was so bad, I had no motivation to start such. So I said, ok, let me try it for a few days...the Rx is for one 5g in the morning and one in the evening. I ended up taking one at noon when my fatigue begins...wow! It's been a game changer. I don't even take the night one..afraid it might make my sleep even worse if that's possible.
Its made such a change that it has improved my mood was well. I don't know if will work for others as well, but it has changed everything for me.