Defrol is a brand name for Deflazacort, a corticosteroid used to treat various conditions involving inflammation and immune system disorders. It is often prescribed for conditions like rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel disease. One of its most well-known uses is in the management of Duchenne muscular dystrophy (DMD), where it helps slow the progression of muscle weakness and improve strength. Deflazacort works by suppressing inflammation and modulating the immune system's activity. It is generally considered to have fewer side effects like weight gain and bone thinning compared to other corticosteroids, such as prednisone, making it a preferred choice for long-term therapy.