INDOMETHACIN (Indocin®) is a nonsteroidal antiinflammatory drug (NSAID). Indomethacin relieves the inflammation and pain associated with rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, and gout. It is also used for muscle aches and pains as well. Your son has the 50mg strength. It is in the same class as aleve, motrin, feldene, etc.