Diclofenac

Diclofenac (CAS 15307-86-5) is a phenylacetic acid derivative and a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX)-1 and COX-2, reducing the production of prostaglandins (PGs) involved in inflammation and pain signaling. It is commonly used as a first-line treatment for acute and chronic pain and inflammation caused by various conditions. Long-term administration induces a rat model of NSAID-related small intestinal injury (enteropathy). Diclofenac was rationally designed based on the structures of phenylbutazone, mefenamic acid, and indomethacin; the two chlorine atoms introduced at the ortho position of the phenyl ring lock the ring at a maximal torsion angle, which is associated with its enhanced potency. It is often combined with misoprostol to prevent NSAID-induced gastric ulcers, was first approved by the FDA in July 1988 under the trade name Voltaren, and is marketed by Novartis (formerly Ciba-Geigy).