Heart risks from Vioxx happen much earlier than believed

A new study led by Queen's University researcher Linda Livesque shows that heart attacks related to the use of Vioxx - a drug once popular for the treatment of pain and inflammation - can occur within the first two weeks of use.

A quarter of patients who suffered a heart attack while taking Vioxx did so within the first two weeks of their first Vioxx prescription, says Prof. Livesque, of Queen's Department of Community Health and Epidemiology. "This demonstrates that cardiovascular risks from taking Vioxx may occur much earlier than previously believed."

Conducted with McGill University researchers James Brophy and Bin Zhang, the findings published on-line in the Canadian Medical Association Journal.

"Our previous study on COX-2 inhibitors, which included Vioxx and Celebrex, evaluated whether there was an increased risk of heart attack while taking these medications; the answer was yes for Vioxx," explains Prof. Livesque. In the current study, funded by the Canadian Institutes for Health Research (CIHR), the pattern of cardiovascular risk in Quibec seniors was assessed over a three-year period.

The additional cardiovascular risk actually decreased with longer duration of use, suggesting that the period of highest susceptibility for most people taking Vioxx may occur earlier than previously believed. The study also documents that cardiovascular risk returns to normal within one month of stopping the drug.

Vioxx was voluntarily withdrawn from the market on September 30, 2004 after a study showed that it doubled patients' risk of heart attacks and strokes after 18 months of use. This study is the first to specifically address the question of the timing of cardiovascular risk associated with COX-2 inhibitors.