The painkiller Vioxx (search), pulled from the market last fall because of reported heart problems and strokes in users, could come back on sale if federal regulators conclude it and similar drugs have benefits that balance the risks.

Dr. Peter S. Kim, president of Merck Research Laboratories, told a joint meeting of two Food and Drug Administration advisory committees on Thursday that new studies indicate the side effects aren't unique to its product.

The advisory panels were concluding a three-day meeting Friday in which they have been assessing drugs known as Cox-2 inhibitors (search), which also include Pfizer Inc.'s Celebrex (search) and Bextra (search), to determine whether they are all risky and, if so, whether they have balancing benefits.

All three drugs have been approved for sale by the government. The committees' recommendations could be the first steps toward rescinding those approvals.

Meeting chairman Alistair J.J. Wood of Vanderbilt University Medical School asked whether the drugs could win approval today, considering the studies that have come to light in recent months.

Kim indicated a positive assessment by the committees might lead Merck to consider bringing Vioxx back onto the market.

If the committees and the FDA conclude that the benefits of this class of drugs outweigh the risks for some patients, "then we would have to consider the implications of these new data" for Vioxx, Kim said.

Asked if he meant the company would consider returning Vioxx to the market, Kim said: "There are unique benefits to Vioxx. The science has progressed and we need to take that science into consideration."

While the committees heard evidence that all drugs in the group can increase the risk of heart attacks, irregular heart beat and strokes, it did note that Vioxx seemed to have more such reports than the other drugs.

On the other hand, Kim pointed out that Vioxx is the only one of the drugs approved for people with certain allergies and did better at preventing the stomach and intestinal problems often caused by over-the-counter painkillers.

Committee members will be asked their opinion on whether all the drugs pose a problem and what should be done. Their recommendations could include increasing warnings, seeking more studies, limiting who can use the drugs or how long they can be used or even ordering one or more off the market.

The evidence is suggestive that there is something going on with each of these drugs, but it is not conclusive, commented Thomas Fleming, chairman of the department of biostatistics at the University of Washington.

Dr. Steven Abramson, chairman of the division of rheumatology at the New York University School of Medicine, said it's possible the problems stem from the ability of these drugs to hamper the Cox-2 enzyme. But he also suggested a study to examine whether similar problems arise from other painkillers, such as ibuprofen.

Dr. Peter A. Gross, chairman of internal medicine at the Hackensack University Medical Center in New Jersey, worried that if the committee did conclude the heart problems were related to the Cox-2 action, patients would all switch to older drugs that can cause ulcers and bleeding problems.