The head of the U.S. drug safety agency said on Tuesday the United States was keeping “all regulatory options open” as it studied data showing increased heart risks from some painkillers.

U.S. health regulators warned on Monday of heart risks connected to over-the-counter painkiller naproxen, which is sold as a generic and under several brand names, including Bayer AG’s Aleve, and as Roche AG subsidiary Roche Palo Alto’s Naprosyn.

The warning follows studies showing increased heart risks in two other prescription painkillers - Merck & Co. Inc.‘s Vioxx, which the company has withdrawn, and Pfizer Inc.‘s Celebrex, which is still on the market.

“We are trying to process all the data that we have and make some determinations as quickly as possible,” Acting Food and Drug Administration Commissioner Lester Crawford told NBC television’s “Today” show.

“It would be premature to say what we are going to do with either one of these drugs, Celebrex or Aleve,” he said. “We will keep all regulatory options open and make some determinations as quickly as possible based on the data.”

DATA UNCLEAR

The recent burst of new data is unclear, at least one rheumatologist told Reuters, and doctors may have to closely match painkillers to patients based on their medical histories.

“It’s really confusing for us and our patients,” said Dr. Gregory Gardner, a rheumatologist who studies joint, muscle and bone-related diseases at the University of Washington in Seattle.

Naproxen and Celebrex are in a group of drugs called non-steroidal anti-inflammatory drugs (NSAID), which include aspirin and ibuprofen. Within that group, Vioxx and Celebrex are part of a class known as Cox-2 inhibitors, along with Pfizer’s Bextra.

Older drugs like aspirin can cause stomach bleeding and ulcers. Newer Cox-2s were designed to prevent such gastrointestinal side effects.

Some medical experts had suspected naproxen might have a beneficial effect on the heart.

When the first signs of a heart risk with Vioxx came to light in 2000, Merck argued the results were skewed by the protective effects of naproxen on other patients taking part in the trial.

Gardner said he would want to see more data on naproxen since it was thought to have a heart-protective effect. “I’m not sure I would change my practices based on a single study,” he said.

NIH-FUNDED TRIAL HALTED

The FDA’s latest warning stems from a National Institutes of Health-funded trial studying certain anti-inflammatory drugs in patients at risk for Alzheimer’s disease. The trial, which included Celebrex, was halted late Friday after early results showed a higher risk of cardiovascular problems.

Celebrex showed “no significant increase” in risk for cardiac trouble or stroke in the trial, the NIH said. But lead researcher John Breitner, head of geriatric research at the Veterans Affairs Puget Sound Health Care System in Seattle, said it was tough to find patients willing to take the drug for the trial in the wake of Vioxx’s withdrawal.

On Friday, Pfizer said a different NIH study investigating inflammation as a cause of cancer showed Celebrex more than doubled the risk of heart attack and strokes. That study was also halted. But another trial to see if the drug could prevent colon polyps did not show such risks, Pfizer said.

Breitner said the late-stage trial, which began in 2001 and was designed to study 2,625 patients for up to 7 years, showed a “fairly impressive signal of increased risk of heart attack and stroke.”

He added that the drugs can be “enormously beneficial” under the right circumstances. “You certainly wouldn’t want people not to use them for bona fide indications. They just shouldn’t take them like candy,” he said.

Other experts said the warning highlights overuse of such painkillers and the consequences of long-term use.

Dr. Gregg Fonarow, professor of cardiovascular medicine at the University of California, Los Angeles, said naproxen and other NSAIDs were approved as short-term treatments for pain relief not as drugs to be used on a daily basis at high doses.

More research needs to be done on how to minimize that risk, possibly by using only low-dose NSAIDs or combining them with low-dose aspirin, Fonarow said.

But Breitner said that is not likely to happen now, at least in humans. “I don’t think anybody is going to be doing any placebo-controlled trials with the non-steroidal drugs going forward,” he said.