Vioxx is out, pulled off the shelves by Merck after a clinical trial revealed that the COX-2 inhibitor increased the risk of heart attacks and strokes in users. Gone, too, is Bextra. Pfizer voluntarily withdrew the drug from the market when further review of data revealed that it, too, can increase the risk of heart attack and stroke. Which leaves Celebrex - slower-acting than Vioxx and Bextra and, for now, with fewer known side effects - as the COX-2 inhibitor used by surgical facilities to tame pain.