The risk of thrombotic events associated with the use of NSAIDs, particularly those selective for COX-2, is mediated via suppression of COX-2-derived prostacyclin formation in endothelial and vascular smooth muscle cells (4,5). Prostacyclin possesses potent anti-thrombotic and vasodilatory effects, and thus acts as a general inhibitor of platelet activation in vivo (2). Traditional NSAIDs also inhibit COX-2 in the vasculature, but the associated risk of thrombosis is mitigated to some extent by inhibition of formation of thromboxane A2 (TxA2), a COX-1-derived PG released by activated platelets that promotes platelet activation and aggregation (1,3). Thus, the risk of thrombosis for a particular NSAID is dependent upon its relative selectivity for COX-2 over COX-1 (3,6). In addition to their effects on vascular PG production, all NSAIDs inhibit renal PG formation, resulting in sodium retention and hypertension, which may further augment cardiovascular risk (1,3,7).