My Age Is 63 And I Am Suffering From Dry

My age is 63 and I am suffering from dry cough since last three weeks. I have used lozenges + antibiotics along with anti allergic tablets but to no avail. During coughing I also feel difficulty in respiratory system. I feel that some kind of salty moisture dropping from nose to the inner side of my throat and it irritates the cough. I will be very helpful if you kindly suggest some kind of medicines.Thanks.