Arthritis Drugs Celebrex-Vioxx Safety in Doubt
"Arthritis drugs Vioxx, Celebrex safety in doubt"
In doubt and may not be as safe as previously thought. Research earlier this year has shown that these drugs increased the risk of heart attacks although a relatively low risk, over those taking a pain reliever. The FDA is debating whether to add information about the increased risk on both drugs' labels. One Wall Street analyst has warned that this problem could have an adverse effect on Merck, the drug company responsible for these drugs be placed on the market - along with Pharmacia, which makes Celebrex, generating $2.3 billion in 12 months to March 31 of this year, Merck having sold $1.7 billion Vioxx during the same 12 months.
Studies done last year showed that patients taking Vioxx had four times the risk of heart attacks over patients taking Naproxen - another pain reliever. Naproxen is also sold under the brands names of Naprosyn and Aleve. The risk of heart attacks increases over time, at about four heart attacks per 1,000 patients. This study was sponsored by the Merck company, which also stated that their research does not show this problem of increased heart attacks with Vioxx.
These two drugs are among the best-sellers of prescription drugs in the world. They cause fewer ulcers that many other drugs given for pain. Richard R. Stover, a pharmaceutical industry analyst at Arnhold & S. Bleichroeder Inc, reported on April 27 that he did his own analysis on what he called "disturbing data" from Merck's study. He stated that he was warning his clients, many of whom were institutional investors holding stock in Merck, that they should watch the issue carefully because it could effect the company's stock price.
Dr. M. Michael Wolfe, chief of the gastroenterology section at the Boston University School of Medicine and a member of the FDA advisory committee stated that there should be a warning, after a review of the issue earlier this year, stating that
There is a current debate going on between some doctors and Merck's scientists as to whether the higher risk of heart attacks is a result of Vioxx causing damage in some patients or to an absence of the benefits that Naproxen may have in protecting the heart, that Naproxen stops or slows the production of thromboxane, which is thought to cause platelet in the blood to form clots, similar to the aspirin effect.
Vioxx and Celebrex have been shown to have the same benefit in protecting the heart.
Several doctors say they are worried about the possibility of heart attacks because many of the arthritis patients taking the drugs are elderly and have a higher risk of cardiovascular problems to begin with. The current debate centers on whether the higher heart attack rate found in patients taking Vioxx is a result of the drug's actually causing damage in some patients or to an absence of the heart-protecting benefits that Naproxen may have.
"Naproxen had a similar anti-platelet effect to aspirin," said Dr. Eve E. Slater, senior vice president of external policy for Merck's research labs, "and those people had fewer heart attacks."
Neither Vioxx nor Celebrex has been shown to have the same heart-protecting benefit.
Slater also said that Stover's report was flawed and biased in favor of Pharmacia. But regulators and some doctors say they still worry that there may be more of a problem with Vioxx.
And even if Vioxx and Celebrex do not damage the heart, the fact that they do not have the heart-protecting benefits of aspirin reduces the ability of the companies to market them as being significantly safer than other pain relievers.
Merck recommended last year that doctors involved in clinical trials of Vioxx consider prescribing low doses of aspirin to patients taking Vioxx if they are at high risk of heart attacks - although low doses of aspirin could increase the risk of ulcers. Ulcers are the main side effect that Vioxx and Celebrex were developed to avoid.
There have been no studies done to determine whether patients have fewer ulcers if they take low doses of aspirin with either Vioxx or Celebrex. In February Dr Maria Lourdes Villalba, at an FDA advisory meeting, stated that Merck had proved Vioxx [Rofecoxib] caused fewer serious ulcers than Naproxen. However, she also state that the potential safety advantage was offset by a higher risk of heart problems,in her opinion. She reported that "Overall, there was no safety superiority of Rofecoxib over Naproxen, mainly due to an excess of serious cardiovascular events".
Dr Villalba also stated that there had been no studies to prove Merck's claim that Naproxen worked like aspirin in decreasing heart attacks. The FDA expressed some concern over the higher rate of heart attacks with Vioxx, stating that this could be caused by the drug's ability to produce blood clots.
"There is still a tremendous benefit with these drugs" reported Dr Eve Slater of Merck.
Margot B, Writer, Web Developer