Lumiracoxib is a COX-2 selective inhibitor non-steroidal anti-inflammatory drug. On August 11, 2007, Australia's Therapeutic Goods Administration (TGA, the Australian equivalent of the FDA) cancelled the registration of lumiracoxib in Australia due to concerns that it may cause liver failure. New Zealand and Canada have also followed suit in recalling the drug. It has never been approved for use in the United States. Lumiracoxib has a different structure from the standard COX-2 inhibitors (e.g. celecoxib). It more closely resembles the structure of diclofenac (one chlorine substituted by fluorine, the phenylacetic acid has another methyl group in meta position), making it a member of the arylalkanoic acid family of NSAIDs. It binds to a different site on the COX-2 receptor than the standard COX-2 inhibitors. It displays extremely high COX-2 selectivity. The mechanism of action of lumiracoxib is due to inhibition of prostaglandin synthesis via inhibition of cyclooygenase-2 (COX-2). Lumiracoxib does not inhibit COX-1 at therapeutic concentrations. Lumiracoxib is used for the acute and chronic treatment of the signs and symptoms of osteoarthritis of the knee in adults.