This was expected, but now it’s official. The agency acted after a recent panel voted to recommend the Glaxo diabetes pill remain on the market, but with stiffer warnings about heart attack risks. The debate followed a controversy that erupted last May, when The New England Journal of Medicine published a meta-analysis showing Avandia increased the risk of heart attacks by 43 percent. Last week, Health Canada severely restricted usage.

“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,” says Janet Woodcock, FDA’s deputy commishr for scientific and medical programs, chief medical officer, and acting director of the Center for Drug Evaluation and Research, in a statement. The “FDA remains committed to making sure that doctors and patients have the latest information about the risks and benefits of medicines.”

For the moment, though, the FDA says there isn’t enough evidence to indicate the risks of heart attacks or death between Avandia and some other oral type 2 diabetes meds are different. [UPDATE: This much is a win, of sorts, for Glaxo, and may help the drugmaker salvage some business.] But the FDA directed Glaxo to conduct a new long-term study to evaluate the potential cardiovascular risk of Avandia, compared to an active control agent. The FDA says it “will ensure” the study is initiated promptly. This is the second Black Box for Avandia, by the way. The first was added for heart failure.

The revision includes the following info:

“A meta-analysis of 42 clinical studies (mean duration 6 months; 14,237 total patients), most of which compared Avandia to placebo, showed Avandia to be associated with an increased risk of myocardial ischemic events such as angina or myocardial infarction. Three other studies (mean duration 41 months; 14,067 patients), comparing Avandia to some other approved oral antidiabetic agents or placebo, have not confirmed or excluded this risk. In their entirety, the available data on the risk of myocardial ischemia are inconclusive.”

The previous upgraded warning, added to certain diabetes drugs (in class of drugs related to Avandia) on Aug. 14, 2007, emphasized that these types of drugs may worsen heart failure, a condition in which the heart does not adequately pump blood, in some patients.

Glaxo is also developing a Medication Guide for patients to provide additional information about the benefits and risks and safe use of Avandia.

To date, no oral anti-diabetes drug has been conclusively shown to reduce cardiovascular risk. Consequently, the agency also will be requesting that labeling of all approved oral anti-diabetes drugs contain language describing the lack of data showing this benefit.

UPDATE: “Avandia remains a valuable medicine for most patients with type 2 diabetes, and when used according to the labeling, has a well described and appropriate safety and effectiveness profile,” Ronald Krall, Glaxo’s chief medical officer, says in a statement. “Given the severity of this disease and the importance of Avandia in helping patients manage their diabetes, we will continue to work with the FDA to conduct more studies about the safety and benefits of our medicine.”