Celecoxib Methyl Ester is an impurity of Celecoxib(C251000). Celecoxib is a selective cyclooxygenase-2 (COX-2) inhibitor. Anti-inflammatory. Used in treatment of familial adenomatous polyposis. Celecoxib is a nonsteroidal anti-inflammatory drug (NSAID). It works by reducing hormones that cause inflammation and pain in the body.Celecoxib is used to treat pain or inflammation caused by many conditions such as arthritis, ankylosing spondylitis, and menstrual pain. Celecoxib is also used in the treatment of hereditary polyps in the colon.