Vioxx is from a class of drugs called Cox-2 inhibitors which block Cox-2 enzymes that are expressed in areas of inflammation, therefore targeting the site of pain. Vioxx is a painkiller used in the treatment of arthritis.
The research has found that these drugs also inhibit the enzyme Cox-1 within the endothelial cells that line all blood vessels.
By suppressing Cox-1 the drugs also inhibit the body's production of prostacyclin, a blood vessel protector that prevents blood clots, therefore heightening the risk of a heart attack.
“It is essential that we have a true understanding of their sites of action so that we can produce new, safe and effective drugs for years to come,” said Tim Warner, a professor at the William Harvey Research Institute at Queen Mary University of London.
The researchers said the results were exciting because they suggested that Cox-2 inhibitors, which are effective pain relievers, could be developed differently so that they did not cause side effects in terms of heart failure and stroke.
Merck's Vioxx had to be withdrawn from the market after research showing that the drug caused adverse effects. The company now faces thousands of lawsuits pertaining to the drug.