If one has Asthma and must use an inhaler, then in such a case does one have to fast? Note that the drug particles in the asthma pump are very small.
As explained in an earlier post, using an asthma pump and inhaling its gas will invalidate one’s fast. As such, if one used an asthma pump for a genuine medical need, one will have to make up the fasts missed (qadha), although expiation (kaffara) will not be necessary.
You state that the drug particles in the asthma gas are very small and minute. However, the ruling of the fast being invalidated is not based on the drug particles being present or otherwise; rather, one’s fast is invalidated by inhaling something that has a perceptible body such as smoke or gas. (See: Maraqi al-Falah with Hashiya al-Tahtawi, P: 660)
Note that, in order for one’s fast to become invalid, one has to inhale the smoke or gas intentionally and deliberately. If the smoke entered one’s nose or throat unintentionally, then one’s fast will not break. (Maraqi al-Falah, P: 660)
Therefore, if an individual was to enter a room full of smoke and he was to intentionally inhale the smoke, whilst the smoke having a perceptible body, then his fast would become invalid. Hence, inhaling gas from an asthma pump will invalidate the fast, regardless of whether there is any nutritional value in the inhalers or otherwise, for the gas has a perceptible body which enters one’s body through a normal channel.
Those who need to use an asthma pump many times a day and find it difficult to fast, have the dispensation of not fasting and paying the Fidya instead. Islam is a religion of mercy and does not order its followers to do something that is beyond their capability. Therefore, chronic asthmatics need not suffer by fasting; rather, if they are genuinely not able to keep a fast or make it up later, they may pay the expiatory payment instead. However, it should be remembered that if one becomes capable of fasting again, one will have to make up for the missed fasts despite paying the Fidya. (al-Fatawa al-Hindiyya, 1/207 and others)
And Allah knows best
[Mufti] Muhammad ibn Adam
Leicester , UK