Dolonex DT 20 mg Tablet used to relieve symptoms like pain, inflammation and joint stiffness associated with rheumatoid arthritis and osteoarthritis. Osteoarthritis is a degenerative joint disease in which the two ends of the joints come together due to the breakdown of a protective covering (cartilage). Rheumatoid arthritis is an auto-immune disease (the body's immune system attacks its tissue), leading to joint pain and damage.