Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) taken or applied to reduce inflammation and as an analgesic reducing pain in certain conditions. It is supplied as or contained in medications under a variety of trade names. As a nonsteroidal anti-inflammatory drug (NSAID), Diclofenac binds and chelates both isoforms of cyclooxygenase (COX-1 and-2), thereby blocking the conversion of arachidonic acid to pro-inflammatory-proprostaglandins. This agent also may inhibit COX-2-mediated tumor angiogenesis. When inhibiting COX-2, Diclofenac may be effective in relieving pain and inflammation; when inhibiting COX-1, it may produce unacceptable gastrointestinal side effects. This agent may be more active against COX-2 than several other carboxylic acid-containing NSAIDs.