Twenty five (25) outpatients with pulmonary (e.g. asthma, cystic fibrosis) or rheumatic (e.g. rheumatoid arthritis, dermatomyositis) illnesses scheduled to receive a brief course ("burst") of prednisone will be enrolled. The subjects will be randomized to receive memantine, riluzole or placebo beginning immediately prior to the corticosteroid therapy and continuing for one week. Measures of cognition and mood will be compared between the two groups at baseline, day 3, and day 7.