The American Society of Health-System Pharmacists reports a shortage of prednisone tablets. I think this shortage bulletin may be a correction for the prednisolone shortage bulletin, which has now disappeared from the ASHP website. See my earlier post, Shortage of prednisolone tablets, for an explanation of what was apparently an error.
There are five manufacturers of prednisone tablets listed in the most recent bulletin. Two give a raw material shortage as the reason for their shortage, but don't indicate whether it is the prednisone itself or a tablet excipient that is in short supply. Three manufacturers don't give a reason for their shortage.