"The jury determined that Merck acted appropriately in the development and marketing of VIOXX and that VIOXX did not substantially contribute to Mr. Dedrick's heart attack," said Phil Beck, of the law firm of Bartlit Beck, Merck's lead trial lawyer in the case, Dedrick v. Merck.

"He had multiple risk factors for a heart attack including a family history of cardiac problems, heavy smoking for many years and he had high blood pressure, high cholesterol and diabetes," Mr. Beck said. "In addition, he had significant atherosclerosis before he began taking VIOXX. Unfortunately, Mr. Dedrick would have suffered a heart attack whether he was taking VIOXX or not."

U.S. District Court Judge Eldon E. Fallon of the Eastern District of Louisiana, who is overseeing all of the federal court litigation, presided over the trial.

Merck faces thousands of lawsuits over the drug, which was pulled from the market in September 2004 after a study showed that it could double the risk of heart attack or stroke if taken for more than 18 months. This is the fifth federal trial to reach a verdict; Merck has won four of those cases, with the fifth decided in favor of the plaintiff. A federal judge, however, threw out the $50 million jury verdict in the Merck loss as "grossly excessive" and ordered a new trial to determine damages.

Merck won the first case, Plunkett v. Merck, in February. The damages portion of the verdict in favor of the plaintiff in the second federal case, Barnett v. Merck, was overturned by Judge Fallon. Merck won the third case, Smith v. Merck, in September and the fourth case, Mason v. Merck, in November. Last month, US District Judge Eldon Fallon, who is responsible for co-ordinating pre-trial procedures in the federal cases, rejected a bid to have all federal lawsuits against Merck brought in connection with Vioxx consolidated in a single national class action against the company.