The Food and Drug Administration wants to regulate Internet search.

At the least, searches that are mediated by regulated medical companies, and tie disease keywords to specific, regulated medical products.

The issue has come to the fore in a warning letter that FDA recently sent to Medical Doctors Research (MDR), a Florida-based researcher and manufacturer of nutritional supplements.

In the January 29th letter, FDA alleges a number of problems with MDR’s manufacturing and promotional activities. But the one that’s catching attention is the FDA’s beef with MDR’s website.

These issues were first spotted in an excellent article by Alex Gaffney of Regulatory Focus, a must-read publication for the drug regulation crowd. (You can follow Gaffney on Twitter: @AlecGaffney)

FDA says that MDR’s website has search capabilities on its web site that allow users to search for a particular terms. The results of these keywords, it said, bring up specific products associated with the search entries, including disease terms.

“Typing the key word ‘cancer’ or ‘diabetes’ into MDR’s product search field located on its website” brings up a number of products, FDA observed. Because those products are associated with that particular search term, the company is thus “implying that its products are intended for use in the diagnosis, cure, mitigation, treatment or prevention of such diseases,” FDA said.

It raises the question of whether FDA has the authority to regulate Internet search when those engines are being manipulated by regulated entities to steer consumers to specific products. And whether drug makers are still accountable when the search terms and the search results are being managed by third party search engines? What, in short, are the parameters for FDA’s authority?

There’s some legal precedent here. Last year, the Third Circuit accepted metadata as evidence of intended use in a case involving Lane Labs’ calcium supplement.

Metadata is basically data about data that sits in a web sites programming. It helps describe the contents and context of specific data files. In this case, it helped link specific ailments with information on treatments.

The legal decision to allow the metadata as evidence was indeed consistent with a claims-based interpretation of intended use. In the Lane Labs case, the seller had to put specific terms on its site in order to trigger the connection between the product information and specific search terms.

But all this is surely different from the usual forms of marketing, underscoring why the letter is attracting some notice — and why FDA (and drug makers) may be on some uncertain, if not shaky ground. It’s compounded by the fact that the agency has steadfastly refused to publish any clear guidance on how its regulation of traditional promotional pieces translates when it comes to web based media like search results.

As Gaffney notes, enforcement of keyword association could prove difficult for FDA. Unlike visible words, metadata sits in the source code and HTML of a page, and is largely invisible to the untrained eye. Other associations, such as those hard-coded into a search engine (as opposed to a static link), may be difficult to find without spending a considerable amount of time on a page. “Still, the warning letter indicates that regulatory officials are intent on targeting those associations when they’re able to be found,” he says.

The larger question, of course, is how the FDA makes best use of its limited resources in pursuing its public health goals. It seems MDR had run afoul of the agency for a myriad of reasons, and the inclusion of a warning around the metadata may have been a gratuitous addition to an otherwise already lengthy list of problems. Or it may have been a calculated attempt by FDA to stake out new policy ground in the context of a firm that was unlikely to garner much sympathy.

In the absence of clear guidance from FDA, one is left to speculate about the agency’s intent by examining its warning letters like one might read Tarot cards. Only time, and perhaps a little divine interpretation, will reveal what the agency’s policy is.