Loxoprofen (INN) is a non-steroidal anti-inflammatory drug in the propionic acid derivatives group. It is marketed in Brazil, Mexico and Japan by Sankyo as its sodium salt, loxoprofen sodium, under the trade name Loxonin, Argentina as Oxeno and in India as Loxomac. It is available in these countries for oral administration, and a transdermal preparation was approved for sale in Japan on January 2006. It is usually used to treat rheumatoid arthritis and osteoarthritis. It is also used to reduce pain and inflammation after surgery, wounds and tooth removal, as well as to bring down fever or ease pain induced by acute inflammation of upper respiratory tract Loxoprofen is a prodrug. When administered orally, loxoprofen sodium hydrate is absorbed from the gastrointestinal tract as an unchanged compound with only a modest gastric-mucosal irritation. It is then rapidly biotransformed into the active metabolite trans-OH form (SRS coordination) with a potent inhibitory effect on prostaglandin biosynthesis to exert its pharmacologic effects. Inhibition of prostaglandin biosynthesis constitutes the mechanism of action of this drug, the site of action being cyclooxygenase.