Deflazacort is corticosteroids used as an anti-inflammatory and immunomodulatory agent. It is used to treat Duchenne muscular dystrophy (DMD). DMD is a rare, inherited muscle disease that occurs usually in children and young adults and is caused by an absence of a protein called dystrophin, which helps keep muscle cells intact. Deflazacort also used to treat inflammation in asthma (inflamed airways), arthritis (pain and inflammation in the joints) and allergies.