Dexamethasone. Molecular model of dexamethasone, a corticosteroid drug used to reduce inflammation and relieve symptoms in a variety of disorders, including rheumatoid arthritis and severe asthma. Corticosteroids inhibit the production of prostaglandins, the chemicals that cause inflammation and assist in the sending of pain signals to the brain. Atoms are represented as spheres with colour coding: hydrogen (white), carbon (blue), fluorine (light green).