ROME, Aug. 25 - Patients worldwide who suffered heart attacks or strokes while taking the painkiller Vioxx are preparing to sue its maker, Merck, exponentially increasing the company's potential liability.
Last week, a jury in Texas found Merck liable in the death of Robert C. Ernst and voted to award $253.5 million to his widow, Carol. Jurors said they concluded that Merck was long aware of Vioxx's potential heart risks but concealed them.
About 4,000 lawsuits are pending in the United States, but there are potentially many more around the world, especially in Europe, where Vioxx, used to relieve the pain of arthritis, was extremely popular.
Merck withdrew it last September, after a study showed a link between long-term use of the drug at high dosage and heart attack or stroke.
In the Texas case, state rules on punitive damages would limit Mrs. Ernst's total award to $26.1 million, and that could be reduced further on appeal. Still, if other cases go against Merck, the litigation could collectively become the biggest medical product liability action in history, exceeding in scope and economic effect the thousands of lawsuits associated with silicone breast implants in the 1990's, which drove their American manufacturer, Dow Corning, to file for bankruptcy protection.
Lawyers are collecting data on thousands of cases, trying to assess whether they should sue Merck in the United States, where rewards are expected to be higher, or in their home countries, where there are likely to be fewer legal hurdles.
Christine Peckham, 52, an Englishwoman who had two strokes in 2001 while taking Vioxx, has already filed court papers in New Jersey.
"Merck has to be made accountable since they knew about this problem at least seven months before I had my first stroke," said Ms. Peckham, who is now legally blind and uses a wheelchair. "I can't work again, and there's no reason why British taxpayers should cover my costs."
It is difficult to tally the exact numbers of suits being filed outside the United States. Lawyers are working on cases in Italy, France, Britain and Australia; in each of those countries, hundreds of thousands of people took Vioxx.
Richard Meeran, special counsel with the law firm of Slater & Gordon in Australia, said the firm had at least 100 strong cases against Merck.
But he expressed concern that huge verdicts in the United States might mean that clients abroad would not have time to pursue their claims effectively.
"Our main concern," he said, "is that Merck will run out of money, given the number of claimants and the size of the U.S. award."
After Dow Corning filed for bankruptcy protection in 1995, European women who contended that their silicone implants had ruptured and caused autoimmune diseases and other ailments received less money than Americans under a compensation plan established by a United States court.
