SUMMARY: Selective COX-2 Inhibitors and Bleeding Risk: An Additional Note - The Medical Letter article on Drugs for Pain (August 21, 2000) stated that the selective COX-2 inhibitors celecoxib (Celebrex) and rofecoxib (Vioxx) do not inhibit platelet aggregation or bleeding time. Perhaps we should have added, as we did in discussing use of these drugs in rheumatoid arthritis (July 10, 2000), that both celecoxib and rofecoxib, if given with warfarin (Coumadin, and others), increase INR and prothrombin time values and may increase the risk of bleeding.