- People who take some commonly prescribed painkillers
for arthritis are at greater risk of developing congestive heart failure,
new Canadian research suggests.The findings could have broad repercussions
because one in four seniors currently takes these drugs.
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- The bestseller, Vioxx, increased the risk of hospitalization
for heart failure by 80 per cent within one year of prescription.
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- Taking a non-steroidal anti-inflammatory drug, such as
ibuprofen or naproxen, increased the risk by about 10 per cent. Taking
Celebrex, another bestseller, did not increase the risk of hospitalization
for heart failure, researchers found.
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- However, among patients already suffering from heart
failure, all the painkillers increased risk substantially, suggesting they
exacerbate existing problems.
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- "The message we should retain is that there are
definitely risks associated with taking these drugs, along with the benefits,"
said Muhammad Mamdani, a senior scientist at the Toronto-based Institute
for Clinical Evaluative Sciences, which conducted the study.
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- He said that, overall, only about 1 per cent of seniors
taking these painkillers are hospitalized for congestive heart failure
each year, but given the large number of patients treated, "these
results are clinically important and suggest a need for careful monitoring
of the cardiovascular effects on patients receiving them."
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- The findings were published in today's edition of the
medical journal The Lancet.
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- The principal drugs analyzed in this study, Vioxx and
Celebrex, are among the most successful and profitable prescription drugs
in history. Launched with much fanfare in 1999, they have largely displaced
cheaper painkillers used to treat arthritis, though they are only marginally
more effective.
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- They are both cyclo-oxygenase-2 inhibitors, meaning they
inhibit production of cox-2, an enzyme involved in pain and inflammation.
The non-steroidal anti-inflammatory drugs do the same, but in a less specific
manner. (The study did not look at the effects of taking acetylsalicylic
acid, or Aspirin, for arthritis.)
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- The drugs also increase blood pressure, which is likely
why the risk of heart failure rises.
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- The main selling point of cox-2 inhibitors is that they
cause fewer gastrointestinal problems than the traditional anti-inflammatory
drugs.
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- Dr. Mamdani said it is "really ironic" that
patients may be trading one side effect, gastric bleeding, for a far more
serious one, congestive heart failure. He also noted that the number of
gastric bleeds and ulcers has probably increased because so many more people
are taking drugs to treat arthritis than before the new drugs were launched.
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- About one in five people over the age of 65 takes cox-2
inhibitors, and about one in three takes the traditional anti-inflammatory
painkillers.
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- Based on the emerging evidence of risks, physicians and
patients alike should rethink this sort of ubiquitous use, said Dr. Mamdani,
who is also an assistant professor in the department of pharmacy at the
University of Toronto.
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- "While these drugs have been greeted with great
enthusiasm, perhaps more judicious prescribing by physicians is warranted,"
he said.
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- The researcher also recommended that arthritis sufferers
"have a serious discussion with their physician before considering
these drugs," particularly if they have a history of cardiovascular
disease or gastrointestinal problems.
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- The new research is based on an analysis of patient records
of almost 45,000 Ontario patients who were prescribed cox-2 inhibitors
or non-steroidal anti-inflammatory drugs between April, 2000, and March,
2001. They were compared to 100,000 others who were not prescribed these
drugs. The average age of those in the study was 75, a population that
has high rates of osteoarthritis and heart failure.
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- There were 7.7 million prescriptions for cox-2 inhibitors
in Canada last year (including almost three million for Celebrex and 3.3
million for Vioxx), with a total value of $475-million, according to IMS
Health Canada, a private company that tracks prescription-drug use. There
were 16 million prescriptions for the non-steroidal anti-inflammatories,
with sales totalling $305-million.
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- About four million Canadians suffer from arthritis. Approximately
350,000 have congestive heart failure.
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- Dr. Mamdani said earlier research helps explain why Vioxx
users are more likely to develop heart failure than Celebrex users. In
head-to-head comparisons, Vioxx raised blood pressure more than Celebrex.
Vioxx also has a longer half-life, meaning it stays in the body longer,
and it has a tendency to accumulate.
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- The researcher said patients should not stop taking their
prescription drugs based on this study. Rather, Dr. Mamdani said, if a
person has concerns, the matter should be discussed with his or her physician
to determine the personal risk and benefits from taking a particular drug.
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