Vioxx was pulled from the market Sept. 30 after a long-term clinical trial indicated some patients suffered heart attacks or strokes. Similar safety questions have risen concerning the related drugs Celebrex and Bextra.
The advisory committees are hearing from government officials, physicians, researchers and the public in three days of meetings before voting on recommendations for these prescription drugs, known as Cox-2 inhibitors.
CBS News Early Show Medical Correspondent Dr. Emily Senay reports the hearings will attempt to answer why these drugs ended up on the market in the first place.
"How was it that risk factors for cardiovascular events like stroke and heart attacks, which were clearly there in some of the early studies, were not taken more seriously?" says Senay. "These drugs were better than approved by the FDA, and yet, we're at the place in time when we're questioning whether or not they should be on the market."
Dr. Steven Galson, acting director of the FDA's Center for Drug Evaluation and Research, said the agency will act rapidly — in the next few weeks — on the committee recommendations. The FDA is not required to accept such recommendations, but generally does.
Galson reminded the group that the drugs in question are important painkillers widely used by people in chronic pain. It is important to balance the risks of drugs with their benefits, he said.
A drug that has a positive risk-benefit balance for the population as a whole, Galson added, may still cause serious problems for some individuals.
The FDA has been criticized for being slow to recognize problems with these drugs.
However, committee chairman Dr. Alistair J. Wood of Vanderbilt University stressed as he opened the session that the committee "is not here to delegate blame or revisit the past."
Vioxx was withdrawn by its manufacturer, Merck & Co. Celebrex and Bextra, made by Pfizer Inc., remain on the market.
The editor of a leading medical journal has questioned whether patients should continue using the drugs.
"Because there are well-established options for treatment of all the approved indications for these drugs, it is reasonable to ask whether the use of the drugs can now be justified," Dr. Jeffrey M. Drazen, editor of the New England Journal of Medicine, said in an editorial published online Tuesday.
In calling the advisory committee hearing Wednesday, the FDA's Center for Drug Evaluation and Research noted that many consumers and scientists have asked whether any Cox-2 drugs should be allowed to remain on sale.
The Health and Human Services Department announced Tuesday that the FDA will establish a new Drug Safety Oversight Board to monitor medicines once they're on the market and will update physicians and patients with emerging information on risks and benefits.
But as CBS News Correspondent Sharyl Attkisson reports, skepticism exists — even within the FDA — over whether such a drug review panel will work.
, who recently studied such drugs as Celebrex and Mobic, an alternative pain medication, with a doctor at Stanford University. Graham said his and other similar studies are not only not being encouraged by the FDA, but they are being withheld from the public.
Graham has been critical of the FDA before, alleging it repeatedly kept the public in the dark over potentially dangerous drugs. He said if the FDA worked in the public interest, it would encourage him to present his study.
"You would think that if the FDA were working for the public and were interested in drug safety that that would be their reaction," Graham told Attkisson.
Dr. Mark Fendrick, an internal medicine specialist at the University of Michigan, said the decision on using the drugs "should be considered one of competing risk and benefits."
"It comes down to the individual and his or her clinician to assess the risks and make the best informed choice," Fendrick said. "Until we know for sure about the cardiological safety of the Cox-2 inhibitors, I believe they should be limited to those individuals who have a risk of stomach injury and those who are at low risk for cardiac problems."
People who have a heart risk or who take aspirin to protect the heart should consider a traditional painkiller, he said.
Many people who take the Cox-2 drugs to avoid stomach problems also take aspirin to protect the heart, he noted, which cancels the gastrointestinal protection of the Cox-2 drugs.
The advisers will also be trying to determine what it is about these drugs that could cause an increase in heart problems.
On Monday, a paper in the journal Archives of Internal Medicine reported on a new analysis that indicates Cox-2 inhibitors raise blood pressure more than conventional pain medications.
A second possibility is that Vioxx directly affects endothelial cells, which line the heart and blood vessels.
A 1999 study of Alzheimer's patients taking Celebrex indicated the patients had four times the risk of heart problems. Pfizer contends that definitive conclusions cannot be drawn from that study. In December, a different study linked Celebrex to increased cardiovascular problems. The company said the results in that study were not consistent with a data the company had collected.