Etoricoxib (etoricoxib) is a highly selective cyclooxygenase-2 (COX-2) inhibitor developed by Merck, chemical name: 5-chloro-6'-methyl-3-4-(methylsulfonate) Acyl)phenyl Chemicalbook]-2,3'-bipyridine. Etoricoxib has a unique chemical structure, that is, methylsulfonyl. The introduction of this group not only increases the selectivity of the drug to COX-2, but also does not cause cross-allergic reactions with sulfa drugs.