Excess mucus

Patient: Hi Doctor I suffer from excess mucus at the back of my throat. I go to my Doctor and he gives me medication to take which clears it up, but as soon as I stop taking it it reappears. I am asthmatic and at the moment I take on a daily basis Symbicort turbuhaler 4.5, Ventolin and Flixonase.Is it safe to take the medication for excess mucus all of the time? As this seems to me the only way I will get any sleep and stop coughing to clear my throat all the time.Thank You