Fenbufen is a non-steroidal anti-inflammatory drug used primarily to treat inflammation in osteoarthritis, ankylosing spondylitis, and tendinitis. It can also be used to relieve backaches, sprains, and fractures. Fenbufen is available as a capsule or tablet sold with the brand names Cepal, Cinopal, Cybufen, Lederfen, and Reugast. Fenbufen acts by preventing cyclooxygenase from producing prostaglandins which can cause inflammation.