Vioxx (Generic: rofecoxib), Merckâ€™s blockbuster painkiller, might be responsible for blood clots in patients after they stopped taking it, write U.S. researchers, said Reuters.
Vioxx, was approved for use in 1999, quickly becoming a bestseller for Merck, with annual sales of $2.5 billion; however, the painkiller was pulled off the market in 2004 after an analysis of patients using Vioxx linked the defective drug to more than 27,000 heart attacks or sudden cardiac deaths in the U.S. from 1999 through 2003. The withdrawal prompted thousands of product liability lawsuits that claimed Merck didnâ€™t properly warn doctors and patients of the drugâ€™s risks.
During the five years it was available, researchers believe Vioxx caused some 40,000 deaths, said Reuters. The new study appears in the Archives of Internal Medicine; findings were based on information Merck provided during legal action against it.
The research shows that those patients taking Vioxx experienced a two-fold likelihood of developing blood clots or dying in the first six months after treatment was discontinued, confirming a prior study that pointed to Vioxxâ€™s negative effects being seen up to one year following discontinuation, said Reuters. Beyond that, said Dr. Joseph Ross of the Yale School of Medicine in New Haven, who worked on the study, it remains unknown what could happen, wrote Reuters. Co-author Dr. Harlan Krumholz, also of Yale, said the study points to issues with other painkillers in the selective COX-2 inhibitors class. COX-2 inhibitors are part of the larger class of NSAIDsâ€”nonsteroidal anti-inflammatory drugsâ€”and include Celebrex (celecoxib), low-dose naproxen, ibuprofen, ketoprofen, and aspirin.
The team looked at 617 patients who stopped Vioxx or a placebo after at least one and a-half years of treatment, said Reuters. The team found that after about six months, 22 patients on Vioxx reportedly developed blood clots; 23 died, according to Reuters. In the placebo group, at four months, six reported blood clots and there were nine deaths. The findings mean that the overall rate of deaths or blood clots is 0.11 annually after a patient stops Vioxx, twice as high as in the placebo group, noted Reuters.
“It indicates a need for more research to understand better how these drugs confer risk,” Krumholz said in an email, quoted Reuters, “and whether we need to know whether people have ever taken these types of medications when we assess riskâ€¦. For future drug evaluation and development we need to pay attention to effects that may manifest after the drug has been discontinued. To me, these results from the Vioxx studies about what happened to people after they stopped taking the drug may even be more important than the studies that showed risk when they were on the drug.”
Of note, a study found that evidence of cardiovascular risks linked to Vioxx might have been realized nearly four years before Merck pulled Vioxx. Since its withdrawal, revelations about the way in which Merck marketed Vioxx have raised serious questions about Merckâ€™s conduct. For instance, a prior Australian Vioxx trial revealed that Merck paid nurses to look through medical records for potential Vioxx patientsâ€”without physician permissionâ€”in the hopes of garnering 100 patients per doctor. Merck also apparently put on a year-end â€œskitâ€ in which sales reps mocked the Journal of the American Medical Association, which published an article discussing Vioxx and issues with its cardiovascular side effects.
One of the most shocking tactics used by Merck was a push in Australia involving a fake medical journal, published by Elsevier, offering it like other peer-reviewed medical journals and with articles reprinted or summarized presenting Merck products, including Vioxx, favorably.