Saying Merck's conduct showed a "wanton and willful disregard of another's rights," the jury added to the $4.5 million it had awarded last week to John McDarby, 77, of Park Ridge, and his wife, Irma.
Last Wednesday, the same panel found that Merck failed to warn of the drug's risks and committed consumer fraud in misrepresenting them to prescribing physicians.
"This is a victory for all of the John and Irma McDarbys of the world, people who are taking medications every single day, who now have at least a chance of making sure that the companies that are making those medications are going to do the right thing," said Jerry Kristal, one of McDarby's lawyers.
Merck, which pulled the blockbuster arthritis drug off the market in 2004 after a study linked it to increased risk of heart attack and stroke, said it would appeal Tuesday's verdict.
"Merck's actions were proper and did not, in any way, call for this award as defined by New Jersey law," said Chuck Harrell, spokesman for Merck's legal team. He said the company's appeal would focus on evidence and testimony state Superior Court Judge Carol Higbee barred from the trial, including limits she set on expert witnesses.
"The evidence was clear that we provided the U.S. Food and Drug Administration with the information about Vioxx that we were required to provide. And under New Jersey law, that means punitive damages should not have been awarded," Harrell said.
After the verdict was announced, Merck shares initially rose 1.5 percent, but were down 15 cents at $34.27 at midday in heavy trading on the New York Stock Exchange.
Tuesday's decision capped a five-week trial that combined two cases: that of McDarby, a retired insurance agent who took the drug for four years, and Thomas Cona, 60, of Cherry Hill.
Jurors rejected Cona's heart attack claim but found in both cases that Merck misrepresented the risks of Vioxx and concealed them from prescribing physicians.
After the verdict, jurors spoke briefly to reporters, calling the verdicts "fair and honest." They wouldn't answer questions.
McDarby, a diabetic who uses a wheelchair, wasn't in court for the verdict Tuesday. His wife said the money - which the couple won't get immediately because of appeals - would go toward giving her husband around-the-clock medical care.
Asked if she had anything to say to Merck, Irma McDarby responded: "The truth shall set you free."
"It's the integrity that's involved, the morality that's involved. All these things are important," she said.
Merck faces about 9,650 Vioxx cases in state and federal courts, and has vowed to try them one at a time.
The trial - the sixth over Merck's once-popular painkiller - was the first involving people alleging use of 18 months or more. That's important because the study that prompted Merck to voluntarily withdraw the drug found that its risks doubled after 18 months' use.
The initial stock-price jolt suggested Wall Street was relieved the punitive award wasn't higher, according to health care analyst Steve Brozak of WBB Securities LLC.
"It would have basically sent a message that this was egregious behavior" by Merck if the jury had imposed the maximum, Brozak said. He said uncertainty over what the jury would do has been a drag on Merck shares.
Harrell, the Merck spokesman, said the verdicts won't change Merck's strategy of defending the Vioxx lawsuits.
Analyst Timothy Anderson at Prudential Financial called the total award of $13.5 million "substantial."
"Seeing as there are 10,000 Vioxx cases already filed, with more likely on the way, (Merck's) Vioxx liability could end up being larger than we have previously anticipated if more verdicts are handed down similar to the one just reached in the McDarby case," Anderson wrote.
By John Curran