Since you are on Zytiga with Prednisone and if your fatigue is so bad that you are having a hard time getting out of bed then increasing your prednisone can help. There was a doctor in a recent conference that talked about his Gleason 9 prostate cancer and the fact that he increased his prednisone because he was having too much fatigue. I mentioned it to someone I know, and he got his doctor to allow him to increase his and it helped a lot with fatigue. Speak to your doctor about this see if more prednisone will help you
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With ADT (and Zytiga) exercise is the usual solution. Walking two or more miles a day and doing some exercises can offset the fatigue. I’ve done it for years and after almost 8 years of being on ADT I still don’t have the fatigue issue. I usually can’t sleep more than six hours a night, and I’m not tired when I get up.

You should also try to do weightlifting or equivalent exercises. Your muscles will deteriorate a lot on ADT, keeping them tuned up with exercise can help offset that deterioration. Brain fog is another issue you may encounter, It just happens when you’re on the drugs for a while. A recent trial called the Patch trial found if one used estrogen it can replace Lupron or Orgovyx, and does not have all of the deleterious effects. Look up the patch trial and speak to your doctor.