Diabetes drug Avandia carries a warning

WASHINGTON — The government slapped a prominent, though confusing, warning on the popular diabetes drug Avandia on Wednesday — telling patients that it may, or may not, increase the risk of heart attacks.

The move is less stringent than steps Canada took last week to restrict the drug's use to hard-to-treat diabetics.

But the U.S. Food and Drug Administration concluded that studies are too contradictory to tell if Avandia really is riskier than other treatments for Type 2 diabetes.

So the FDA described the controversy in a black box on Avandia's label — the most severe type of warning the agency can require — pending further research. Unlike most black-box warnings that urge strong caution, Avandia's says, "The available data on the risk ... are inconclusive."

"It's still an open question," said Dr. John Jenkins, FDA's drug chief. Still, he said, "We want to make sure health care providers and patients are aware this signal of risk has been identified."

Patients may need a medical dictionary to interpret the new warning. It says Avandia may be associated with "myocardial ischemic events such as angina or myocardial infarction."

In layman's terms, that's chest pain or a heart attack. Manufacturer GlaxoSmithKline PLC is to develop a pamphlet that will come with each bottle putting the warning in easier-to-understand language.

Glaxo also agreed to FDA's demand for a major study directly comparing Avandia and its competitors' heart effects. The study will begin by next November and won't end until 2014, but the FDA will order interim checks to see how patients are faring and if it's possible to settle the issue any sooner.

"It isn't as if we're going to be clueless until 2014," said Dr. Janet Woodcock, FDA's chief medical officer.

For now, Type 2 diabetics who also have heart disease or are at especially high risk for it should talk with their doctor about Avandia's potential heart effects as they decide among treatment options, FDA advised.

In contrast, Canada's drug regulators last week withdrew approval of Avandia as a stand-alone therapy except for patients who can't tolerate older competitors. Health Canada announced that Avandia should be used only in combination with certain other drugs for hard-to-control blood sugar.

Dr. Steven Nissen of the Cleveland Clinic, who first brought the heart attack issue to public attention, said he preferred Canada's approach — but that Wednesday's warning is important, if imprecise.