I've never used prednisone to help with my lung problems. I did however use it once when I was having sever joint pain, it got so bad I couldn't sit up by myself, could barely walk and I couldn't even bend my fingers. At first my rehmatologist thought it might have been some kind of viral infection, but it came back a few days after I stopped taking the prednisone and then my doctor thought it was CF related arthritis...but then it just went away and I didn't need the prednisone anymore.