ATLANTIC CITY, N.J. — A jury awarded $9 million in punitive damages Tuesday to a man who blamed his heart attack on Vioxx, finding that manufacturer Merck & Co. failed to warn about the risks of its arthritis drug and misrepresented those risks to physicians.

The damages are in addition to $4.5 million already awarded to John McDarby, 77, of Park Ridge, who suffered a heart attack after four years on Vioxx, a painkiller taken by more than 20 million Americans and an estimated 700,000 Canadians before being pulled off the market.

In its only other loss in a Vioxx case, Merck was ordered last August to pay $253 million to the widow of a man who died after taking the drug for a short time. That amount will be reduced because the law in Texas, where the case was heard, limits punitive damages.

The drug company said it would appeal.

Merck faces about 9,650 Vioxx cases in state and federal courts, and has vowed to try them one at a time.

In Canada, some 3,000 people are estimated to have joined various class action suits against the company. Many claim to have suffered heart attacks or strokes while on the medicine, or are relatives of patients who have died.

Tuesday's decision in New Jersey 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, N.J..

Cona said he took the drug for 22 months before his 2003 heart attack, but he couldn't prove it. His prescription records showed only enough for about seven months' use, and the six-woman, two-man jury rejected his claim that Vioxx was to blame.

In both, the jury said Merck misrepresented the risks of Vioxx and concealed them from prescribing physicians.

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 jury could have awarded McDarby $22.5 million in punitive damages, or up to five times the amount of the compensatory damages he had been awarded. Punitive damages are designed to punish companies for misbehaviour.

The verdict was the first time since New Jersey passed a product liability act in 1995 that a drug company was ordered to pay punitive damages.

"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.

"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.

Merck shares fell 16 cents to $34.26 in morning trading on the New York Stock Exchange after initially rising 1.5 per cent in the immediate wake of the verdict announcement.

The initial rise indicated Wall Street was relieved that the jury didn't award the maximum $22.5 million, health care analyst Steve Brozak of WBB Securities LLC said.

"It would have basically sent a message that this was egregious behaviour'' 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.