11/15/2007- Avandia, the world's best-selling diabetes drug last year, will carry the Food and Drug Administration's strongest warning on the possible risk of heart attacks, the agency announced yesterday.

GlaxoSmithKline agreed to provide the warning, outlined in a black box in Avandia's prescribing information, while the FDA continues its assessment of Avandia's safety, including whether it poses greater dangers than competing products such as Actos, made by Takeda Pharmaceutical.

U.S. sales of Avandia, used to treat Type 2 diabetes, dropped by about half after a May 21 report in the New England Journal of Medicine linked Avandia to a 43 percent increased risk of heart attacks. The FDA's action fell short of restrictions on Avandia that were put in place in Canada and Europe in recent weeks.

Health Canada withdrew approval for Avandia as a stand-alone therapy last week and said it should be given mainly with the older drug metformin. European regulators said it should be used only in select groups of patients.

Glaxo has agreed to the FDA's request to conduct a new trial of Avandia, and the agency will ask that the medicine be compared directly with Actos and perhaps other drugs, Janet Woodcock, acting director of the agency's Center for Drug Evaluation and Research, said in a conference call with reporters.