Studies list more problems with pain-killing drugs
Two studies offer more evidence about the dangers of some painkillers, adding kidney problems to heart concerns already raised with the drug once sold as Vioxx, researchers said on Tuesday.
One report from Boston's Brigham and Women's Hospital and Harvard Medical School said an analysis of 114 studies involving more than 116,000 people showed that rofecoxib (the chemical name for Vioxx) "was associated with increased renal and (heart) arrhythmia risks."
Why the drug would cause kidney damage is unclear, it added.
Merck & Co Inc. withdrew Vioxx from the market in September 2004 after a three-year study showed it doubled the risk of heart attack and strokes in patients taking it for at least 18 months.
A second report from the University of Newcastle, New South Wales, Australia, said a look at 23 studies confirms findings of an increased risk of heart problems with Vioxx that could be found "during the first 30 days of treatment. This conclusion is consistent with a recent reanalysis ... which contradicts the original suggestion that the vascular risk was only seen after 18 months."
The studies were published in this week's Journal of the American Medical Association (JAMA) along with an editorial from David Graham, a physician who works for the U.S. Food and Drug Administration but whose comments were labeled as his own views and not those of the regulatory agency.
Merck is facing more than 11,500 product liability lawsuits from people claiming to have been harmed by Vioxx.
"What the studies are going to do is provide substantial support for the opinions being expressed by the plaintiffs' experts, and that will serve to increase their credibility and persuasiveness to juries," said Frank McClellan, professor at Temple University's Beasley School of Law.
"Those studies will also be used to cross-examine and impeach Merck's experts who testify that there is no link between the drug and the injuries," McClellan said. "The impact could be profound in the outcomes of the trials."
Merck said it still believes the data confirm the increased heart risk begins only after the medicine had been taken for 18 months.
Merck said in a statement the observations in the JAMA articles and opinions expressed in an accompanying editorial regarding potential increased risks with short-term Vioxx use "are not supported by the current weight of clinical data."
The Australian analysis also found that celecoxib -- sold as Celebrex by Pfizer Inc. -- was not associated with heart problems at a dose no greater than 200 milligrams a day.
It said that its review "raises serious questions about the safety of diclofenac, an older (analgesic) drug" which is sold more in Europe than the United States.
"In conclusion ... diclofenac seems to share this risk and, unlike celecoxib, it appears to be harmful at commonly used doses. We believe there are grounds for reviewing its regulatory status," the report added.
In his editorial, Graham said the studies demonstrate that Vioxx "increases the risk of acute myocardial infarction at low and high doses" and that "there is no initial 18-month period of immunity from risk."
He said Celebrex increases heart risk at doses higher than 200 milligrams per day and several other non-steroidal anti-inflammatory drugs (NSAIDs) increase risk, including diclofenac, meloxicam, indomethacin and "probably" ibuprofen, while studies agree naproxen is "neutral" for heart attack risk.
Graham added that for most patients with arthritis or other conditions requiring chronic pain relief "naproxen appears to be the safest NSAID choice from a cardiovascular perspective." Naproxen is commonly sold as Aleve by Bayer Corp.