That's mainly because of concerns that embracing emerging Web 2.0 tools could run afoul of Food & Drug Administration regulations governing the advertising and promotion of branded drugs. The FDA hasn't squarely addressed the role of social media in drug advertising to date. But an agency official offered some insight on the subject in a recent interview with Mark Senak, a Fleishman Hillard executive in Washington, D.C. who separately runs the EyeonFDA blog.

The upshot is that the FDA doesn't categorically prohibit pharmaceutical companies from engaging in social media. "It's not the medium, it's the message," explained Dr. Jean Ah Kang, special assistant to Tom Abrams at the FDA's Division for Drug Marketing, Advertising and Communications, in charge of Web 2.0 policy development.

In the interview with Senak earlier this month, Kang emphasized that the key to advertising in any medium is for drug makers to present labeling information prominently and accurately and communicate all material risks.

Asked about original promotional material posted to a social site that might be subsequently altered by users, Kang said the agency takes into account third-party involvement in social media. A key consideration would be whether the marketer, or any companies working with it, had any role in prompting user-made changes.

While brands like Skittles may have fully embraced the consumer-in-control movement, the drug companies are inherently more conservative when it comes to a category that invites consumer participation and self-expression.

In September, the FDA sent a warning letter to Shire Pharmaceuticals in connection with a video promotion on YouTube for the drug Adderall XR. The agency said both the video and a Web page for Adderall overstated its efficacy of and that the video omitted important risk information. But the FDA did not specifically object to the use of YouTube itself as a promotional vehicle.

While Kang wouldn't discuss the FDA's process for better defining how pharmaceutical companies can use social media, she said: "We do recognize the importance of social media, like Web 2.0, and we recognize that it is reality and it is here to stay."

Even so, it's likely that big pharma will remain reticent about plunging into social media marketing, barring more explicit guidelines from the FDA. "We've found most pharmaceutical advertisers have been sitting on the sidelines and asking us not to pitch social media in our programs," said Michael Keriakos, co-founder and president of Waterfront Media, parent of health portal Everyday Health.

He estimates that packaged goods companies are spending about 10% of budgets on social marketing initiatives, while pharmaceutical companies may devote less than 2%. Chris Schroeder, CEO of competing health site HealthCentral, agreed.

"We've had several advertisers who have and are experimenting here, but most are still being very cautious --'most' meaning the legal departments," he said. "I've not see folks rush to it yet, even with this statement, but we've been viewed as a 'safe' group that really works with them."

Beyond social media, pharmaceutical companies are also bracing for possible new restrictions on direct-to-consumer advertising under President Barack Obama's administration. During the presidential campaign, Obama proposed regulating DTC advertising specifically as part of broader health care reform.

But interest in expanding into social media remains. In a post this week about Kang's comments on EyeonFDA, Nielsen Online analyst Melissa Davies, who covers the pharmaceutical industry, wrote: "I have had several conversations recently with clients who are ready to move beyond social media listening and are wondering how they can engage in the environment."

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