Does Inhaler Break Your Fast?
Question

There are many types of medication for asthma, including the well-known puffer. There is medication in the form of a capsule which is placed in a special container to be inhaled via the mouth; it is ground up in the container and then inhaled. And there is a device, in which the medicine is put in liquid form, then the device is placed over the face and the liquid comes out in a mist like a gas. Are these things regarded as breaking the fast?
Praise be to Allah.Types of asthma medication 
There are many kinds of medication for asthma, some of which break the fast and some do not. The most well known of these medicines and treatments are puffers , oxygen, vaporizers and capsules. 
Does inhaler break your fast?
The puffer uses a compressed gas that is used by the patient, which reaches the lungs via the trachea to expand the lungs. It is not food or drink or anything resembling them. 
The scholars of the Standing Committee have ruled that the fast is not broken by using this kind of medicine. This is also the ruling of Shaykh Ibn ‘Uthaymin and most of our scholars. 
Does oxygen break your fast?
With regard to oxygen , it too is neither food nor drink. Based on this, it may be used when fasting with no problems. 
Do vaporizers break the fast?
With regard to vaporizers, these are usually devices which change the medicine – which is usually carried in a sodium base – from liquid to gas and fine particles. The medicine is placed in a small vessel and when the device is activated, air is blown at high speed which causes the medicine to turn into a gaseous form, so it can be inhaled by the patient either via a mask that is placed over the mouth, or by means of a small tube that is placed inside the mouth. 
It is inevitable that some drops of water and salt will reach the stomach via this device, and the patient will not be able to avoid that. Based on this, if he uses this method, he should break his fast and he should make up that day later on. 
Do capsules break your fast?
Capsules contain the medicine in the form of a fine powder. These capsules are placed inside a special device which crushes the capsules in order to release the medicine, which is inhaled from the device via the mouth. Using these capsules invalidates the fast, because some of this powder mixes with the saliva and goes down into the stomach. 
Shaykh Muhammad al-Salih al-‘Uthaymin (may Allah have mercy on him) was asked: 
Some people have asthma and need to use puffers when fasting. What is the ruling on that? 
He replied:
“Some people are affected by constriction of breathing which is known as asthma. We ask Allah to keep us and them safe and sound. Two types of medicine are used, one of which is known as capsules. This type breaks the fast because it is a powder that has substance and can enter the stomach. The fasting person should not use it in Ramadan except in the case of necessity. If he uses it in the case of necessity then he has broken his fast and may eat and drink for the rest of the day, and make up another day in its place. If it so happens that this sickness is ongoing, then he is like an old man who has to feed one poor person for each day, and he does not have to fast. 
The second type of asthma medicine is a gas which contains nothing but air which opens the airways so that the person can breathe easily. This does not break the fast; the fasting person may use it and his fast is valid.” (19/question no. 159) 
The Shaykh (may Allah have mercy on him) was asked: 
There is a person who has asthma and cannot read Quran without using oxygen. Can he use it during the day in Ramadan? 
He replied: 
“If it is not essential for him to use oxygen, then it is better for him not to use it. The fasting person is not obliged to read Quran such that we would say that he should use it in order to read Quran. But some of those who are afflicted with this sickness say, “I cannot stop using it, and if I do not use it I fear that I may not be able to breathe.” So we say there is nothing wrong with using this oxygen, because according to what we have heard it does not reach the stomach, rather it reaches the veins and makes it easy to breathe. If that is the case, there is nothing wrong with it. 
But there is a type of pill that is given to asthma patients, which is a capsule that contains powder. It is not permissible to use this when observing an obligatory fast, because when it is mixed with saliva it reaches the stomach, in which case it breaks the fast. If a person has to use it, then he should break his fast and make up that day later on. If he has to use it all the time, then he should break his fast and feed one poor person for each day.” (19/question no. 163) 
For more, please see this answer: What Breaks Your Fast
And Allah knows best.