New research has uncovered how some cox-2 painkillers increase the risk for both heart attacks and stroke. The once popular cox-2 drugs, Vioxx and Bextra, were pulled off the market in 2004 and 2005, respectively, after research showed that both raised the chances of cardiovascular trouble. Meanwhile, Celebrex, a painkiller in the same drug class that remains on the market, carries a "black box" warning alerting patients to potential heart risks. Now, a team of scientists from the University of Pennsylvania in Philadelphia say that, although cox-2 inhibitors are very good at inhibiting the workings of the cox-2 enzyme --...