The majority of U.S. health experts on a panel debating the merits of Type 2 diabetes drug Avandia have voted to keep the controversial drug on the market, though 12 panellists recommended pulling it from shelves over concerns it carries too high a risk of heart problems.

Twenty of 33 experts voted Wednesday afternoon against withdrawing the GlaxoSmithKline-made drug from the market;  instead; they recommended revising the label to include additional warnings and restrictions beyond the warnings already on the label.

Ultimately, panelists said the dozens of contradictory studies of Avandia did not show strong enough evidence to justify removing a drug used by hundreds of thousands of patients.

"I didn't want to take away a drug without definitive evidence that it was bad for those few patients who need it," said the University of Missouri's Lamont Weide, who voted to leave the drug on the market with new restrictions.

Although the FDA itself will make the final call on the status of the drug in the coming months, it usually follows the advice of its panels.

Health Canada, too, had been listening closely to the panel's recommendations, particularly since Canadians filled 1.373 million prescriptions of Avandia and its cousin, Actos, in 2009 to control Type 2 diabetes.

Medical experts are warning people taking Avandia not to change their medication without consulting their doctor. The American Diabetes Association, the U.S. Endocrine Society and the American Association of Clinical Endocrinologists say patients concerned about the debate should discuss their treatment with their doctor.

GSK responded to the panel's decisions by saying its view remains that controlled clinical trials are the best way to assess the benefits and risks of medicines and that six such trials on Avandia have been reported since 2007.

"Together, these trials show that Avandia does not increase the overall risk of heart attack, stroke or death. As a result, we believe that when used in the appropriate patient and in accordance with labeling, Avandia is a safe and effective treatment option for type 2 diabetes," the campnay said in a statement.

Avandia, also called rosiglitazone, works by helping control blood sugar by increasing the body's sensitivity to insulin. But a number of studies have pointed to evidence that it may also raise the risk of heart attacks in patients who take it.

In 2007, the FDA commissioned a similar group of experts in light of dozens of studies suggesting Avandia increased the risk of heart attack.

The panel back then gave the all-clear for keeping the drug on the shelves, saying they weren't convinced the risks of the drug outweighed its benefits. However, the FDA decided at that time that the drug's warning label should be strengthened, and called for additional study.

Now, with more studies pointing to problems -- and pressure from public safety advocates -- the FDA decided to review the matter again.

Dr. David Juurlink, a specialist in internal medicine at Toronto's Sunnybrook Health Sciences Centre, and a drug safety researcher, says analyzing the safety of Avandia has been tricky.

One reason is that the potential toxicities caused by the drug, such as swollen ankles and fluid around the heart, which leads to heart failure, are also caused by the disease itself.

"So it's really hard to separate the effects of the drug from the effects of the disease," Juurlink told CTV News Channel Wednesday afternoon, after the panel's vote.

Though GlaxoSmithKline insists the current research doesn't show an increased cardiovascular risk from using the medication, Juurlink has long suggested that doctors should err on the side of caution.

"This drug causes blood sugar to go down, and that's a good thing," Juurlink said. "But the comparison drug here, Actos, does the same thing in terms of blood sugar and many of the panellists made the point that…the data suggested that Avandia is more dangerous, it isn't perfect, but there's a recurring signal that it might be more dangerous than Actos and it doesn't have a particular advantage."

Juurlink published a study last summer that found people who took Avandia had a higher risk of serious heart disease events like heart failure, strokes and even death.

In May, Juurlink and the U.S. advocacy group Public Citizen called on the FDA to pull the plug on a large international trial comparing Actos and Avandia -- called the TIDE study -- saying it's unethical to continue it given the safety concerns about Avandia.

The FDA panel decided Wednesday that study should go forward. Results will not be available for at least five years.