US regulator to rule on pain drug US food and drug regulators will decide on Friday whether to recommend the sale of painkillers that have been linked to a high risk of heart attack and stroke. The Food and Drug Administration (FDA) advisory panel will give its verdict after hearing evidence for three days. The painkillers - called COX-2 inhibitors - are sold under brand names such as Celebrex and Vioxx. Vioxx was withdrawn from shops last year but Merck said it would consider selling it if it gets FDA approval. The FDA has been asked to decide if the benefits to patients justify the increased risks. Putting Vioxx back on the shelves is likely to boost profits at Merck and make easier any legal battles with people who claim to have been injured by the drug, analysts said. Merck voluntarily stopped sales of Vioxx on 30 September, a move which caused the firm's fourth-quarter earnings to slide to $1.1bn (£581m), from $1.4bn a year earlier. Merck's shares tumbled more than 10% on the news and the company has had to set aside millions of dollars to cover the cost of Vioxx-related litigation. Alarm bells were rung by a research note called Approve which showed that the risk of heart attack and stroke doubled in patients who had been taking the drug for at least 18 months. The Cox-2 inhibitors were developed by drug companies, including Merck and Pfizer, because they cause users fewer stomach problems than other painkillers. Pfizer is still selling its Celebrex and Bextra products, though investigations have suggested that they may also be harmful to the heart. Merck's announcement of a possible reintroduction of Vioxx caught analysts by surprise. Merck's head of research Peter Kim said that it withdrew Vioxx "based on the information that was available to us at the time, knowing there were alternative therapies". He went on to say that things have since changed in the light of new reports. "Given this new information, its is not clear that the cardiovascular risk observed in Approve makes Vioxx unique in the class of similar drugs marketed in the US," Mr Kim explained. On Thursday, David Graham from the FDA's Office of Drug Safety told the advisory panel that "there really doesn't appear to be a need for Cox-2" inhibitors. According to calculations presented to the US Senate by Dr Graham in November, Vioxx may be linked to as many as to 56,000 American deaths. Facing stem criticism for its handling of the Vioxx case, the FDA said on Tuesday that it will create an independent body to oversee the safety of drugs already in the market place. European regulators, meanwhile, ruled on Thursday that patients who have had heart disease or a stroke should not take Cox-2 inhibitors. The European Medicines Agency also said doctors should be "cautious" about giving the drugs to patients who have risk factors for heart disease.