It is a maintenance medication to prevent exacerbation and flare up. It will replace your antibiotic and Prednisone. It targets the inflammation in the lungs and airways and if you are having trouble breathing you have inflammation in your airway or lungs. You can still use your rescue inhaler if needed but in my case I have not had to use mine since I started the injection. I just use my maintenance inhaler twice a day and it's Breztri.