Suggest Treatment For Severe Bronchitis Caused Due To Morphine Allergy

Im allergic to morphine and have severe bronchitis right now. They want me to take the codeine syrup but Im afraid of having a reaction because Ive been told it converts to morphine in my system. They are in the same drug family I think so Im always trying to be careful? I have to get something to help with this cough. No over the counter medicine is helping at all.