A panel of medical experts on Monday recommended that the Food and Drug Administration allow

GlaxoSmithKline

(GSK) - Get Report

to market an over-the-counter version of the prescription diet drug Xenical.

The panel voted 11 to 3 to support the company's petition for a lower-dose version of Xenical available without a prescription, according to media reports. The FDA isn't bound by recommendations from its advisory committees, but it usually follows their suggestions. If the FDA approves an over-the-counter form of Xenical, it would be the first nonprescription diet drug endorsed by the agency.

Glaxo purchased the U.S. rights for a nonprescription form of Xenical from the Swiss drug company

Roche

in July 2004. Roche has sold prescription-strength Xenical in the U.S. since 1999.

The major questions posed by panel members Monday and by an FDA staff report issued Friday included how safe the drug is without a doctor's supervision and how well patients would understand how to take the drug without abusing it.

An FDA staff report questioned whether a proposed label for the nonprescription version adequately expressed potential risks for the drug, which is known generically as orlistat. "Preliminary evidence suggests that nonprescription labeling may not adequately direct the safe use of orlistat,'' said the staff report.

For example, in a test of label comprehension, only 35% of diabetics realized they shouldn't take the drug. Only half of the patients taking warfarin, an anticoagulant, or cyclosporine, which prevents organ rejection, understood they shouldn't take Xenical, the FDA staff said.

FDA staffers routinely issue reports in advance of advisory committee meetings, analyzing data and recommending questions that panel members should ask drug manufacturers.