MATTHEW PERRONE AP Business Writer WASHINGTON (AP) — GlaxoSmithKline is scrambling to shore up the safety image of its weight loss pill alli, after watching sales dive on news that federal regulators are investigating the drug. Alli has received a high-profile marketing push as the first over-the-counter weight loss medication, complete with television ads and a celebrity endorsement from country singer Wynonna Judd. However, Glaxo has spent the last two weeks on damage control after the Food and Drug Administration said it was probing more than 30 reports of liver damage in patients taking alli and Xenical, the prescription version of the drug. Glaxo executives say sales of alli dropped 10 percent after the Aug. 24 announcement, even though the FDA stressed it had established no direct link between the drug and liver problems. Glaxo rushed out print advertisements in national newspapers and magazines, stressing the extensive safety testing behind the drug. "It's the most widely studied weight loss medicine ever, with over 100 clinical studies involving 30,000 patients," Howard Marsh, chief medical officer of Glaxo's consumer products division, said in an interview. U.S. sales of alli climbed 12 percent from a year ago to $42 million in the last quarter, though they have come nowhere near the blockbuster numbers originally expected by Wall Street after the drug's 2007 launch. Analysts say the brand has been hurt by lower consumer spending as well as unpleasant side effects, such as anal leakage. The latest marketing push has been fairly aggressive, though it may be needed to protect a brand that has been buffeted by negative publicity, said John Mack, editor and publisher of Pharma Marketing News. "I think they're very concerned about all the side effects that are being thrown against the product, whether they're real, potential or imaginary," said Mack. "There's been a lot of talk about all those things and they don't seem to be able to get out from under them." The FDA first requested information from Glaxo about liver toxicity more than a year ago, but company executives said they had no advance warning of the August announcement. "I think it's fair to say we would have liked to have had some advance notice of this, because we were forced into a position where we had to respond very quickly," said Roger Scarlett Smith, president of Glaxo's Pittsburgh-based consumer product division. FDA spokeswoman Siobhan Delancey said the agency never gives early notice of such actions. "Many of these actions have the potential to significantly affect stock prices, and to provide advance warning may give certain investors an unfair advantage," Delancey said in a statement. Glaxo is not the first drugmaker to be caught off guard by so-called early communications, which the FDA first implemented in 2007. The FDA has since issued early communications on a slew of drugs, including Merck's asthma drug Singulair and Pfizer's smoking-cessation pill Chantix. The agency ultimately added a "black box" warning to Chantix and bolstered language about suicidal behavior, depression and anxiety on Singulair. The FDA implemented the new policy after coming under fire for acting too slowly on problems with blockbuster drugs like Merck's painkiller Vioxx, which was linked to heart attack and stroke after approval. Mark Senak says any company regulated by the FDA should expect to see earlier action as Obama administration officials begin sharpening their focus on protecting public health. "I think this is just part of the bigger picture of moving the agency to a more pro-active public health stance," said Senak, an attorney who advises companies as a consultant for communications firm Fleishman-Hillard. The FDA said last month it had received 32 reports of serious liver injury among patients taking alli and Xenical between 1999 and October 2008. Twenty-seven patients had to be hospitalized, and six of those suffered liver failure. The FDA release did not mention that only two of the 32 reports involved alli, something Glaxo and the FDA later confirmed. Xenical, which is marketed by Roche, has been available via prescription for 10 years. Glaxo stresses that more than 6 million people in the U.S. have taken the drug, making two incidents of liver damage a micro-fraction of a percent. Executives also note that as many as 20 percent of overweight people already have liver damage, due to excess fat in the organ. The FDA has not set a deadline for concluding its investigation, but has advised patients to continue taking the drugs as directed.