Study shows how painkillers raise heart risk

WASHINGTON, April 14 (Reuters) Painkillers called COX-2 inhibitors may increase the risk of heart attacks by raising blood pressure and making the blood more likely to clot, researchers said.

They do so by the same mechanisms that they use to reduce pain and inflammation, said University of Pennsylvania School of Medicine researcher Dr Garret FitzGerald yesterday, who led the study.

But the finding shows that a new generation of anti-inflammatory drugs could avoid the problem, FitzGerald reported in the Journal of Clinical Investigation.

''Although these results are in mice, not people, they raise an exciting possibility which can be tested in humans,'' FitzGerald said.

The COX-2 inhibitors were originally designed to be a safer long-term treatment than aspirin and other analgesics for arthritis and similar pain. They fell under a cloud when it was found they could raise the risk of heart problems.

Merck and Co pulled its drug Vioxx from the market in September 2004 after a study showed it doubled the risk of heart attack and stroke in people who took Vioxx for at least 18 months. A jury on Tuesday awarded 9 million dollars in punitive damages to a New Jersey man who blamed Vioxx for his heart attack and more than 7,000 other people have sued.

Pfizer Inc suspended sales of its COX-2 inhibitor Bextra and now includes a strong ''black box'' warning for its COX-2 Celebrex, the only such drug now on the market.

FitzGerald has for years had a theory that COX-2 drugs depress a protective fat called prostacyclin, while leaving unaltered a harmful one called thromboxane.

He and collaborator Colin Funk, now at Queen's University, Ontario, genetically manipulated mice and tested them.

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