The U.S. Food and Drug Administration announced that it instructed GlaxoSmithKline PLC to put a new warning label on its Avandia (active substance: rosiglitazone) diabetes drug. The new label should emphasize there may be an increased risk for heart attacks associated with taking the drug.

"FDA has moved expeditiously to review the cardiovascular risks of this drug so that we could inform patients and doctors at the earliest possible time of our findings," said Janet Woodcock, M.D., FDA's deputy commissioner for scientific and medical programs, chief medical officer, and acting director of the Center for Drug Evaluation and Research. "FDA remains committed to making sure that doctors and patients have the latest information about the risks and benefits of medicines."

However, it should be emphasized that the Food and Drug Administration did not find evidence that Avandia can be associated with higher risks of heart attacks or death compared to other type 2 diabetes drugs. The FDA has requested GlaxoSmithKline to carry out a new long-term study to evaluate the potential cardiovascular risk of Avandia, compared to an active control agent.

Rosiglitazone is manufactured either as a stand-alone drug (Avandia); or in combination with metformin (Avandamet); or with glimepiride (Avandaryl). The new black-box warning is also expected to apply to these other two diabetes drugs sold by Glaxo, Avandamet and Avandaryl, because they contain rosiglitazone. Rosiglitazone may also be of benefit to a subset of patients with Alzheimer's disease not expressing the ApoE4 allele, but this claim needs further investigation.

While the drug was the company's third-best-selling product last year, with revenue of $2.3 billion, sales of the drug plummeted 38 percent in the most recent quarter compared to 2006. Diabetes mellitus type 2 is a metabolic disorder characterized by insulin resistance, relative insulin deficiency, and hyperglycemia.