Consumer Reports on Health, "The COX-2 controversy. Are newer arthritis drugs safer?"

          The newest class of arthritis drugs, called COX-2 inhibitors, is supposedly easier on the stomach than standard medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs). That notion has made them by far the best-selling prescription pain relievers. But only one of two large, recent clinical trials clearly supported that idea - and that same trial raised the possibility that the COX-2 drugs may increase the risk of heart attack and stroke.
          The new, multicenter studies each involved some 8,000 patients, lasted six and nine months, respectively, and compared a COX-2 inhibitor - either celecoxib (Celebrex) or rofecoxib (Vioxx) - with one or more traditional NSAIDs. The celecoxib study found a trend toward fewer gastrointestinal complications from the COX-2 drug during the first six months. But that difference was statistically significant only for a secondary measure, not the main one. Data for one year, not yet published, showed less reduction in risk.
          The rofecoxib study did find significantly fewer gastrointestinal problems from the COX-2 drug. However, it also found that users of the drug had more heart attacks than the traditional NSAID users. The study could not determine whether that difference occurred because the COX-2 drug increases heart-attack risk (in theory by facilitating blood clots) or because the older NSAID reduces that risk (by inhibiting blood clots).
          A recent study in the Journal of the American Medical Association tried to clarify that question by comparing heart-attack rates in both COX-2 groups with the combined rate in the placebo groups of other studies. The risk was significantly higher for both celecoxib and rofecoxib. However, our consultants say that comparing heart-attack rates in different studies of different patient populations is too imprecise to shed much light on the heart-hazard question.