In response to a question regarding the use of asthma inhalers during Ramadan.
Unfortunately, the user of any inhalers whether for asthma or any other purpose, during the fast is not permitted. The use of inhalers breaks and violates the fast.
Some argue that the medicinal particles enter the lungs and not the stomach, however even though the route of entry is via the trachea into the lungs, inevitable some particles will enter the oesophagus and enter the stomach. Aside from this, the ruling is that anything which crosses the bottom/back of the throat, violates the fast.
By Shaykh Abu Yusha Yasin of The Suyuti Institute