thanks for asking your question I completely understand your question cough of long duration and associated rhinitis can be seen in diseases like allergic rhinitis , sinusitis , post nasal drip and cough alone for longbduration can be seen in tuberculosis and cough with wheeze can be aeen in bronchial asthma so now u need to consult a pulmonologist who can request for a sputum afb , chest xray and a spirometry if needed . this will render you safe and all yhe diseases which are a possibility can be ruled out no need to panic continue with the treatment , the drug you mentioned can easily taken for a long duration , dont worry thanks / regards feel free to ask more questions may god bless you with good health