Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used for the treatment of inflammatory pain. Pain is a highly subjective experience, and selecting an analgesic regimen that provides optimal pain relief for a specific patient can be challenging. Moreover, patients often express a preference for a particular NSAID, raising the possibility that the efficacy in relieving pain is variable among individuals. However this has never been studied systematically. The clinical decision-making process has been further complicated by the recognition that NSAIDs cause serious thrombotic adverse events in some patients (1). Elucidating the factors that influence an individual patient's risk of cardiovascular complications and the likelihood of analgesic efficacy will enable clinicians to prescribe NSAIDs rationally in order to maximize their therapeutic benefit while minimizing the risk of adverse cardiovascular events.