The Vioxx warning
October 10,
2004
FOR FOUR years, researchers have been pointing to disturbing signs that
the popular painkilling drug Vioxx causes heart attacks and strokes with
long-term use. Last week the pharmaceutical giant Merck voluntarily withdrew the drug from the market
after a recent study confirmed this side effect. The rise and fall of
Vioxx highlights the need for longer studies before the Food and Drug
Administration approves new medications that will often be taken by
patients for extended periods of time and lack the urgency of life-saving
treatments. At $2.5 billion in annual sales, Vioxx is the biggest-selling
drug any company has ever recalled. In its five-year history it became
widely prescribed as a painkiller for arthritis patients, since it did not
cause ulcers or stomach bleeding. The study that confirmed its link to
cardiovascular problems was actually designed to determine whether Vioxx
might also prevent the recurrence of colon polyps that could become
cancerous.
But critics of the drug had long voiced the suspicion that it caused
heart problems. In a 2000 study, Vioxx did somewhat better than another,
generic painkiller in not causing ulcers or gastrointestinal bleeding.
When that study also showed more nonfatal heart attacks in Vioxx patients
than in those taking the other drug, Merck attributed the difference to a
heart-protective effect it said the other drug had. By 2002, the FDA had
seen enough evidence of heart-related problems with Vioxx to require a
label warning. It should have also required a thorough study at that
point.
In the test of Vioxx as a preventer of colon polyps, the heart problems
emerged after 18 months of daily use. The testing that led to the drug's
original approval lasted just 12 months.
The most immediate task for the FDA is to order long-term studies of
possible cardiovascular problems in users of prescription painkillers
similar to Vioxx, such as Celebrex. But after the Vioxx recall and others
in recent years, the agency should also examine whether it is letting
medications come onto the market before their long-term effects have been
sufficiently tested.
Critics of the FDA in the pharmaceutical industry and Congress often
take the agency to task for delaying unnecessarily the approval of new
drugs. While that criticism might be valid in the case of life-saving or
life-extending drugs for patients with cancer or other extreme conditions,
the only reason for speedy approval of drugs like Vioxx, which simply
improve on other painkillers, is to give the maker a longer period under
patent protection. However, there is a risk that a short trial period will
not detect side effects in drugs for chronic conditions that might be
taken by some patients for years. Patients with cardiovascular problems
worsened by Vioxx have paid for that rush to market. 
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