Merck & Co ended a run of defeats in the courts yesterday after a New Jersey jury ruled that its Vioxx painkiller was not responsible for the heart attack of Elaine Doherty, a 68-year-old woman.

And in the second crucial element in the case, jurors concluded that while Merck had not given adequate warning to Doherty herself about the cardiovascular risks associated with Vioxx, it had provided enough information to her physician.

Doherty had multiple risk factors for heart disease, including high cholesterol, diabetes, high blood pressure and obesity, argued Merck, so Vioxx was not the primary cause of her heart attack.

Merck pulled Vioxx off the market in September 2004 after a study showed the COX-2 inhibitor doubled the risk of heart attacks and strokes when taken for 18 months or more. Critically, Merck been considered to be most vulnerable to defeat in cases where long-term use of Vioxx had been proven, but in this event it emerged victorious despite the fact that Doherty had been on the drug for more than two years. Prior to that Merck won two cases involving short-term users of the drug.

In April, a Texas jury awarded $32 million to a man whose heart attack was deemed to be caused by Vioxx, even though he had taken the drug for only a few weeks. Meanwhile, earlier the same month a case involving the first long-term user of the drug also found against the company, awarding compensatory and punitive damages of $13.5 million. Merck is appealing against both the rulings.

The drugmaker has insisted it intends to fight each case brought against it alleging damages from Vioxx, but prior to this ruling there had been speculation the company may be forced into a settlement agreement on unfavourable terms.

The company is said to be wary of entering into any form of settlement agreement for fear that thousands more claimants would come forward – over and above the 16,000 or so that have done so already – and inflate the cost of damages.

Kenneth Frazier, senior vice president and general counsel of Merck, said: "Today's outcome reinforces our commitment to defend these cases on a case-by-case basis."