A 26-year-old woman, who has been suffering from rheumatoid arthritis for 8 months, has edemas of her elbow, radiocarpal, knee, and ankle joints, and rheumatoid nodules in the area of her elbow joints. Complete blood count shows ESR of 57 mm/hour and C-reactive protein (+++). X-ray of the joints reveals marked osteoporosis. What medicine would be used as the basic therapy in this case?