Lumiracoxib is a highly selective and potent cyclo-oxygenase (COX)-2 inhibitor, with a novel structure that conveys weakly acidic properties and a unique pharmacological profile. It is rapidly absorbed, with a relatively short plasma half-life. In well designed clinical trials of 1-52 weeks' duration in patients with osteoarthritis (OA) or rheumatoid arthritis, the efficacy of oral lumiracoxib 100-400 mg/day in decreasing pain intensity and improving functional status was greater than that with placebo and similar to those with nonselective NSAIDs or celecoxib 200mg once daily. In single- and multiple-dose well designed trials in patients with acute pain associated with primary dysmenorrhoea, dental or orthopaedic surgery or tension-type headache, lumiracoxib 100-800 mg once daily was more effective in relieving acute pain than placebo or controlled-release oxycodone 20 mg, and was at least as effective as selective COX-2 inhibitors or nonselective NSAIDs. Lumiracoxib was generally well tolerated in clinical trials, with a similar overall tolerability profile to those of placebo and other COX-2-selective inhibitors. In a large 52-week safety trial in patients with OA, lumiracoxib 400mg once daily had a rate of gastrointestinal ulcer complications that was approximately one-third to one-quarter of that of ibuprofen 800 mg three times daily or naproxen 500 mg twice daily. Lumiracoxib was not associated with an increase in cardiovascular events.