I was on Prednisone 2 times during my infusions and 1 more time a month or 2 after IPI all starting at 100 mg and then taper down rather quickly. Muscle weakness can be a serious side effect from steroids but I would also be worried about IPI affecting adrenal glands. But the good news is IPI worked and I went from multiple nodes affected to just 1 enlarged pelvic node. So don’t worry about it not working but do let Dr know about the side effects. The have the potential to be serious.