Celebrex linked to heart risks

Maker says painkiller shows hazards in studies, but keeps it on market

FDA under fire over drug safety

December 18, 2004|By David Kohn | David Kohn,SUN STAFF

Pfizer Inc. warned yesterday that its popular painkiller, Celebrex, might raise the risk of heart attack. Many experts responded by recommending that patients stop using the drug.

Critics said the announcement raises safety questions about all anti-inflammatory drugs in the same category and shows that the Food and Drug Administration is not ensuring the safety of the nation's drugs.

"It's more indication that the FDA isn't doing its job," said Dr. Sidney Wolfe, head of the consumer activist group Public Citizen, which has warned of problems with Celebrex since 2001. The group called yesterday for the FDA to ban Celebrex and a similar Pfizer drug, Bextra.

The company did not remove Celebrex from the market, but the FDA advised doctors and patients to consider other painkillers. Many experts said the news confirmed suspicions that all so-called COX-2 inhibiting drugs could have intrinsic cardiovascular hazards.

"Now I think the argument is over. This is clearly a class effect," said Dr. Garrett Fitzgerald, a University of Pennsylvania cardiologist and pharmacologist who studies COX-2 inhibitors and heart disease.

Another drug in the class, Vioxx, was withdrawn from the market by Merck & Co. in September after studies showed that it raised heart attack risk.

Last week, the FDA warned that Bextra, another COX-2 inhibitor, might also pose cardiovascular hazards. Celebrex, Vioxx and Bextra are the only three drugs in that class approved by the FDA, although others are marketed in Europe.

FDA Commissioner Dr. Lester M. Crawford recommended yesterday that doctors consider switching patients to other medicines. He said the agency will evaluate the data from a Pfizer study showing the heart attack risks of Celebrex.

But many experts said COX-2 inhibitors shouldn't be used at all until questions about their safety were answered. "All three drugs have been shown to increase heart attacks and strokes," said Marcia Griffin, an epidemiologist and internist at Vanderbilt University. "Why should consumers be using these drugs?"

Griffin and two colleagues wrote a letter to the New England Journal of Medicine recommending that patients stop using Bextra. The letter was due to be published Dec. 23, but after Pfizer's announcement, the journal released the letter yesterday. Griffin said yesterday that in light of Pfizer's announcement, she would include Celebrex in her warning.

COX-2 inhibitors are a class of drug that reduces pain by blocking an inflammatory chemical called cyclooxygenase-2 (COX-2). When introduced in the late 1990s, they were seen as a breakthrough because they caused fewer stomach problems than anti-inflammatories such as aspirin and ibuprofen.

Pfizer made its announcement yesterday, less than 24 hours after getting results from a study being conducted by the National Cancer Institute of the National Institutes of Health.

Researchers there were examining whether high doses of Celebrex could ward off colon cancer. But after the Vioxx withdrawal, NCI scientists began re-examining their data.

They found that subjects taking 400 mg of Celebrex were 2.5 times as likely to have serious heart problems as those taking a placebo. At a dose of 800 mg, the risk was 3.4 times higher.

Researchers immediately halted the study, which involved more than 2,000 patients.

But Pfizer also noted that a similar Celebrex study it conducted on its own showed no increased risk of heart problems .

The NIH said yesterday that it's examining 40 current studies involving Celebrex and has asked researchers to tell the patients involved about possible risks.

At the FDA, officials yesterday described the latest Celebrex results as surprising. "It's not consistent with all the other data," said Dr. John Jenkins, director of the agency's Office of New Drugs.

But other researchers disagreed. "We predicted that this might happen 5 1/2 years ago," said Penn's Fitzgerald. He said animal studies strongly suggested that COX-2 inhibitors could damage the cardiovascular system.

Most experts said the heart risks from Celebrex - and perhaps other COX-2 inhibitors - are probably small for those who use the drugs at low doses for a few days or weeks. But at larger doses over months or years, the hazards are likely to be higher, especially for those with heart disease or at risk for it.

"I believe you can take them over the short run, but probably not over the long term," said Johns Hopkins University cardiologist Charles Lowenstein. He said that even before the Pfizer announcement, he recommended that his patients avoid COX-2 inhibitors.

The problem, experts say, is that so many patients take Celebrex and Bextra for chronic pain over long periods in high doses. For rheumatoid arthritis, the recommended dose is 200 mg to 400 mg a day.

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