* More than 800 people tried to register for FDA event

* Lilly: hesitant to use social media without FDA clarity

* FDA urged to communicate with Wikipedia, other sites (Recasts with meeting under way; adds Eli Lilly, other comments, background)

WASHINGTON, Nov 12 (Reuters)- Drug makers, Internet companies and nonprofits packed a hearing into what is a gray area for U.S. health regulators: how far Twitter, Wikipedia, blogs and other social media can go in promoting drugs.

The two-day public hearing, convened Thursday by the Food and Drug Administration, aims to find out if the agency needs to specifically regulate how drugs and medical devices under its oversight are promoted on the Internet.

“Consumers turn to the Web more often than the traditional channels they historically relied on” such as family, friends and doctors, Wayne Gattinella, chief executive of WebMD, a site for health information, said during a presentation.

The FDA already has strict rules governing what drug makers can say in magazine, newspaper and television advertisements, but the fast-evolving online world is a Wild West when it comes to what is -- and is not -- possible to regulate.

Some frequently used websites have inaccurate or incomplete information, and there is a lack of consistency about the quality of information on websites like Wikipedia and Drugs.com, Diana Zuckerman, president of the National Research Center for Women and Families, said in her remarks.

“Because the risk of providing inaccurate information on medical products is so high, the FDA needs to establish ongoing relationships with... websites consumers are relying on,” she said.

Other speakers slated for the event included representatives of drug companies such as Eli Lilly & Co LLY.N and Pfizer Inc PFE.N, as well as Internet heavyweights like Google Inc GOOG.O and Yahoo Inc YHOO.O.

More than 800 people tried to register for the FDA event, which was held in a meeting room that seats 350, said Thomas Abrams, director of FDA’s direct marketing arm. Abrams was one of a dozen FDA officials who will analyze the public comments to decide what action, if any, the agency needs to take.

An Eli Lilly executive for regulatory affairs told the FDA panel that lack of clarity about the agency’s guidelines have prevented the company from participating heavily in social media and discussing its products online.

John Mack, editor of online newsletter Pharma Marketing News, and a blogger, said the FDA should require drug makers apply certain “tags” or ID codes to Twitter posts to monitor conversations about a product.

TRICKY QUESTIONS

The Pharmaceutical Research and Manufacturers of America industry group this week urged the FDA to adopt a standard safety logo for Web content that would link to FDA-approved information about a drug or device. [ID:nN09273270]

The logo suggestions attracted much interest from FDA officials, who peppered Jeffrey Francer, PhRMA’s assistant general counsel, with questions. Francer said the logo’s use should be governed by the FDA.

The FDA announced the meeting, called the “Promotion of Food and Drug Administration-Regulated Medical Products Using the Internet and Social Media,” in September.

Among questions the FDA asked presenters to address was: what criteria should be used to determine when third-party conversations are subject to “substantive influence” by companies that market the products being discussed.

The FDA also asked speakers to discuss what online messages drug makers are responsible for, how companies can achieve balance in ads within the confines of a 140-character Twitter message and when linking is appropriate or misleading.

The hearing comes after the FDA sent warning letters about drug marketing online to 14 companies in April, including Eli Lilly and Merck & Co Inc MRK.N. The agency told both companies that its ads online for certain products were misleading because they did not contain any risk information.

The FDA is webcasting the hearing at: here (Reporting by Deepa Seetharaman; Editing by Tim Dobbyn)