Parecoxib-d5 sodium is the deuterium labeled Parecoxib sodium. Parecoxib Sodium (SC 69124A) is a highly selective and orally active COX-2 inhibitor, the proagent of Valdecoxib. Parecoxib Sodium is a nonsteroidal anti-inflammatory agent (NSAID) and inhibits prostaglandin (PG) synthesis. Parecoxib Sodium can be used for the relief of acute postoperative pain and symptoms of chronic inflammatory conditions such as osteoarthritis and rheumatoid arthritis in vivo[1][2].