KEENE, Tex. — In Carol Ernst’s eyes, two years ago she won a measure of justice.

On Aug. 19, 2005, a Texas jury awarded Mrs. Ernst $253.5 million after concluding that Merck & Company and its painkiller Vioxx had caused the death of her husband, Robert, in 2001. At a news conference after the verdict, Mrs. Ernst said she was pleased that jurors had punished Merck for hiding Vioxx’s heart risks. “This has been a long road,” she said. “I just know that it was a road that I had to run and I had to finish.”

But her comfort was premature. Merck, the third-largest American drug maker, appealed the verdict — which Texas laws on punitive damages automatically reduced to $26.1 million. Until higher courts rule on the appeal, Merck is not obligated to pay. So Mrs. Ernst, 62, has yet to receive any money.

In fact, none of the 45,000 people who have sued Merck, contending that they or their loved ones suffered heart attacks or strokes after taking Vioxx, have received payments from the company. The lawsuits continue, for now in a state of legal limbo, with little prospect of resolution.

In combating the litigation, Merck has made an aggressive, and so far successful, bet that forcing plaintiffs to trial will reduce the number of Vioxx lawsuits and, ultimately, its liability.

Promising to contest every case, Merck has spent more than $1 billion over the last three years in legal fees. It has refused, at least publicly, to consider even the possibility of an overall settlement to resolve all the lawsuits at once.

The strategy’s successes, from the view of Merck and its shareholders, are clear. In the last year, the company has won most of Vioxx cases that have reached juries. Though its stock plunged immediately after the Robert Ernst verdict, it has since risen 80 percent, easily outpacing those of other big drug makers. And estimates of Merck’s ultimate liability, once as high as $25 billion, are now closer to $5 billion, said C. Anthony Butler of Lehman Brothers.

The Merck executive most closely associated with the company’s strategy, Kenneth Frazier, its general counsel, has prospered. In July, Mr. Frazier was promoted to president of the global human health division, where he oversees the marketing and sales forces, half of Merck’s 60,000 employees.

When Merck withdrew Vioxx from the market in 2004, after a clinical trial found that the drug increased the risk of heart attacks when taken for 18 months or more, some predicted the company’s doom. More than 20 million people in the United States had taken Vioxx, and some scientists estimated that as many as 100,000 might have suffered heart attacks.

Merck said it had adequately warned patients and doctors of Vioxx’s heart risks and that it never knowingly endangered patients.

The pace of Vioxx-related lawsuits, after soaring in 2005 and 2006, has fallen slightly this year, as plaintiffs’ lawyers shy away from cases where they lack strong evidence that their clients took Vioxx for several months before having a heart attack. Lawyers have withdrawn several cases as they were about to go to trial.

“It seems to have worked quite well,” Peter Schuck, a professor at Yale Law School who specializes in complex litigation, said of Merck’s strategy. “They have discouraged the plaintiffs’ bar from litigating these cases.” The legal system is not set up to try thousands of cases at once, and nearly all Vioxx lawsuits are caught up in the pretrial process.

Plaintiffs’ lawyers have tried to get the courts to combine all the potential suits into a single class action. But judges have rejected that tactic. Because the facts of individual cases can vary greatly, each case must be tried separately, courts have ruled.

So far, fewer than 20 Vioxx suits have reached juries, an average of 9 in each of the last two years. At this rate, the backlog of Vioxx cases will take years to work through and many plaintiffs may die before they get their day in court.

Even if they win, it will take years for plaintiffs to be compensated. Merck has appealed every case it has lost. In the case of Mrs. Ernst, if her award is upheld, she will not be paid before 2010 at the earliest, her lawyer, W. Mark Lanier of Houston, said.

After the 2005 verdict, analysts wondered how Merck would overcome evidence presented in the case, showing that the company had been concerned about Vioxx’s potential heart risks as early as 1997, two years before it began selling the drug.

“The possibility of increased C.V. events is of great concern,” a Merck scientist, Dr. Alise Reicin, wrote in a 1997 e-mail message.” “C.V. events” is medical shorthand for cardiovascular incidents like heart attacks. “I just can’t wait to be the one to present those results to senior management,” Dr. Reicin’s message continued.

Other documents offered at the trial showed that in March 2000, Dr. Edward M. Scolnick, then Merck’s top scientist, said a clinical trial had confirmed Vioxx’s risks. Documents also showed that Merck resisted efforts at the Food and Drug Administration to add clear warnings to Vioxx’s label.

Even after losing the Ernst case, Merck did not back down from its strategy of fighting every case.