Duchenne muscular dystrophy
First line
Drug of choice for Duchenne muscular dystrophy in boys from age 4–5. Per DMD Care Considerations 2018 and 2023, deflazacort slows loss of muscle function, delays loss of ambulation by 2–3 years, and reduces scoliosis risk. Versus prednisolone it produces fewer cushingoid features and less weight gain, so Spain and Italy often prefer it. Dose 0.9 mg/kg/day, lifelong, with scheduled monitoring of growth, bone density, and vision.