Naproxen is used in musculoskeletal and joint disorders such as ankylosing spondylitis, osteoarthritis and rheumatoid arthritis including juvenile idiopathic arthritis. It is also used in dysmenorrhea, headache including migraine, postoperative pain, soft-tissue disorders, acute gout, and to reduce fever. Naproxen is usually given by mouth as the free acid or as the sodium salt.