FRIDAY, April 22, 2005 (HealthDay News) -- New research on Norwegian smokers presented at a major U.S. cancer conference this week found that long-term use of certain over-the-counter painkillers raises risks for heart attack and stroke.
As the dust settles on the news reports of the study, a number of experts say the findings raise more questions than they answer -- and are certainly no reason for anyone to toss out their Advil, Motrin or Aleve.
"This is a small, retrospective study, and it needs to be judged with that in mind, rather than making sweeping recommendations," said study co-researcher Dr. Andrew Dannenberg, the director of cancer prevention at New York Presbyterian Hospital-Cornell in New York City.
Americans seeking safe, effective pain relief have endured a rather unnerving seven months. First, in September, the prescription cox-2 inhibitor Vioxx was pulled from the market after a major study linked its long-term use to heightened cardiovascular risk. Then, earlier this month, the U.S. Food and Drug Administration yanked a second cox-2, Bextra, from pharmacy shelves, citing similar concerns.
A third cox-2, Celebrex, remains available to U.S. consumers, but the FDA has mandated that it carry a strong "black box" warning label indicating the potential for long-term heart risks.
Cox-2s, which target a specific enzyme, are a subset of a larger class of pain relievers called non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDs include prescription and non-prescription forms of ibuprofen (such as Advil and Motrin), naproxen (Aleve) and aspirin.
The FDA's mandate now applies to all these drugs, which must carry stronger warning labels citing concerns that they, too, might pose a long-term risk to the heart.
Up until the Monday release of the Norwegian study at the American Association for Cancer Research's annual meeting, there was little evidence backing up those concerns, however.
Dannenberg and his colleagues in Norway didn't set out to ascertain the cardiovascular risks of NSAIDs, he said.
"The purpose of our study was to evaluate individuals who utilized traditional NSAIDs, and see whether or not they were protected against developing tobacco-smoke induced oral cancers," he explained.
In fact, their study of 908 Norwegian smokers found that daily use of non-cox-2 NSAIDs such as aspirin, ibuprofen or naproxen for more than six months did cut the risk for oral cancer by about two-thirds, compared to non-users.
"However, we also noticed that, despite the reduced risk of oral cavity cancer, there was no obvious prolongation of life" in this NSAID-using group, Dannenberg said.
"That was puzzling," he added.
Digging deeper, the researchers discovered that long-term NSAID users also faced twice the risk of dying from heart-related problems, compared to participants who took a non-NSAID pain reliever, acetaminophen (Tylenol).
"These data suggest that the increase in cardiovascular risk observed with selective cox-2 inhibitors like Vioxx or Bextra is not unique, but rather extends to traditionally used NSAIDs" such as ibuprofen and naproxen, Dannenberg said.
"This supports the FDA's decision to extend the black box warning to these traditional NSAIDs," he added.
Yet Dannenberg said his team's findings should also be taken with a big grain of salt.
"First of all, this is retrospective, not a prospective study," he pointed out. Retrospective studies -- where scientists comb through old data looking for patterns -- are never as reliable as prospective trials, where researchers are able control and record events as they unfold.
And he noted the patients were all smokers, "presumably high-risk individuals for cardiovascular disease already. These results might not extend to nonsmokers," he said.
Other experts agreed the study has serious limitations.
"For example, people who tend to be on long-term painkillers, they often have other diseases and problems that might increase their risk for vascular disease," said Dr. Philip Greenland, a spokesman for the American Heart Association and a co-author of the AHA's recently released guidelines on NSAID use.
"So, is it any great surprise that people who are on these drugs are also at higher risk than people who aren't?" he said.
Greenland also noted that the study found a slight increase in cardiovascular risk for aspirin users -- a finding that flies in the face of much larger, better-controlled trials suggesting aspirin protects the heart.
Dr. Mark Fendrick, a professor of internal medicine at the University of Michigan and an expert on NSAID use, said consumers also need to understand that even a doubling of risk might not amount to much in terms of their absolute risk.
"The [relative] cardiovascular risk [in the Norwegian study] might have been doubled, but that might mean it doubled from 1-in-1,000 to 2-in-1,000," he pointed out. "You need to understand the absolute risk."
Fendrick believes much more study is needed before consumers start emptying their medicine cabinets.
"Right now, long-term, placebo-controlled trials -- the gold standard -- are simply not available to medically assess the potential for traditional NSAIDs to increase the risk of adverse cardiovascular events," he said.
In that sense, Fendrick said, this small, retrospective study "does add more fuel to the fire to start that placebo-controlled trial, to answer these questions in a definitive way."
Until that time, Fendrick, Dannenberg and Greenland agreed that consumers should simply read labels closely and follow directions for whatever drug they take.
"No one has reported that short-term use of these medications has ever been associated with any adverse outcomes," noted Greenland, who is also chairman of the department of preventive medicine at Northwestern University's Feinberg School of Medicine, in Chicago.
As for long-term use -- typically meaning more than a week or two -- "to be on the safe side, people should try to be on the lowest dose possible and they should not take any drug over the long term unless they absolutely need it," Greenland said. "Of course, those are all instructions that have already been on drug labeling for a long time."
To learn more about pain-relieving medication, visit the Arthritis Foundation.