Yes, I Have Green Looking Phlegm In My Cough And

Yes, I have green looking phlegm in my cough and I spit it out,doctor prescribes Azithromycin tablets 250 mg and prednisone 20 mg. I have been taking this for the last 4 years on and off more on. I do not like taking the prednisone because it has really weakend my immune system. I just took it a month ago and again I am sick with cough and chest congestion. What else can I take (over-counter) besides prednisone to not weaken my immune system, I catch a cold very easily. I have asthma and take proair 160 mg twice a day. Also on Losartan 25 mg a day and metoprolol tartraate 12.5g a day. Thank you