Inhaled corticosteroids are medicines containing corticosteroids such as beclomethasone, budesonide, ciclesonide, flunisolide, fluticasone, or mometasone in a preparation designed to be inhaled through the mouth. Inhaled corticosteroids act directly in the lungs to inhibit the inflammatory process that causes asthma. Inhaled corticosteroids help to prevent asthma attacks and improve lung function. They may also be used in the treatment of certain other lung conditions, such as chronic obstructive pulmonary disease (COPD).
Because inhaled corticosteroids deliver the medicine directly into the lungs, much smaller doses of corticosteroid are needed to effectively control asthma symptoms compared to what would be needed if the same medication was taken orally. This also reduces the likelihood of side effects.