is for opening up of airways.it will help you in breathing better..
your doctor has prescribed then he must have had some reason...
you can get done your sputum examined for the organism.get done culture and sensitivity and gram stain and zeil neilson staining.
you can start up with antibiotic like levofloxacin
750 mg once daily for 5 days with Cough
syrup.and report back.