Pfizer makes Celebrex, a cox-2 inhibitor pain medication, similar to Merck’s Vioxx. Merck voluntarily pulled Vioxx off the market when product tests revealed increased incidence of heart problems for patients who took Vioxx.

Today, Pfizer announced that a National Cancer Institute cancer prevention study found that Celebrex caused double the incidence of heart problems in patients who took 400-800 mg/day compared to non-Celebrex taking subjects. But another Pfizer study run by the NCI showed no increased risk. The 400-800 mg doses are four times the recommended dosages.

And it gets worse for Pfizer:

Earlier this month, the Food and Drug Administration said it was adding a warning to the labels of another Pfizer drug, Bextra, noting a risk of potential heart problems associated with the use of Bextra in people who have recently had heart bypass surgery. Bextra is also a cox-2 inhibitor type of drug.

Unlike Merck, however, Pfizer is not removing Celebrex or Bextra from the market.