Hawzah News Agency – Q: There is a medicine for asthma patients, which is in the form of a spray containing a vapor-borne powder which enters the patient’s lungs through the mouth providing him relief. At times, asthma patients need to use it several times a day. Is it permissible to fast while using such a spray?
A: If it is used only to dilate the respiratory canal, it does not invalidate fast.
Source: https://www.leader.ir/en/book/32/Practical-Laws-of-Islam