NEW ORLEANS — Merck & Co.was stung with two major legal setbacks over the withdrawn painkiller Vioxx yesterday when a federal jury ordered the drug-maker to pay $51 million to a heart-attack victim, and a state judge in New Jersey overturned a November verdict favoring the company.

In New Orleans, the jury found that Merck “knowingly misrepresented or failed to disclose” information about Vioxx to retired FBI agent Gerald Barnett’s doctors. It said Mr. Barnett, of Myrtle Beach, S.C., should get $50 million in compensatory damages. And it added $1 million in punitive damages, saying Merck “acted in wanton, malicious, willful, or reckless disregard for the plaintiff’s rights.”

In New Jersey, state Superior Court Judge Carol Higbee ruled evidence uncovered since the November verdict showed that Merck withheld information showing heart attacks could come with use of Vioxx for less than 18 months, an attorney, Christopher Seeger said.

Mr. Seeger represents Frederick Humeston, of Boise, Idaho, who had a heart attack in September 2001.

“Merck consistently said throughout the trial that you had to be on Vioxx for 18 months to be at increased risk of a heart attack,” Mr. Seeger said. “And that was false. They had data that people were having heart attacks within weeks.”

Merck said it would appeal the New Orleans verdict and was considering its options in the New Jersey case.

“Both the finding and the amount of damages were totally uncalled for in this case because Merck acted appropriately in providing information to the medical, scientific, and regulatory communities in a responsible and appropriate manner,” a senior vice president for Merck, Kenneth Frazier, said of the New Orleans verdict.

As for the New Jersey case: “We have a significant disagreement with the court’s decision because the evidence presented to the jury during the course of a seven-week trial in 2005 showed that Merck behaved appropriately with respect to Vioxx and also that Vioxx was in no way related to Mr. Humeston’s heart attack,” Ted Mayer, of Hughes Hubbard & Reed, a member of Merck’s national defense team, said in a news release.

Ruling from the bench in Atlantic City, Judge Higbee based her decision on new depositions and an editorial published in the New England Journal of Medicine asserting that Merck withheld “very important heart attack data from the public, and also that they didn’t correctly state the data in the trial,” Judge Seeger said.