The latest studies on Avandia, GlaxoSmithKline's blockbuster diabetes drug, have raised enough questions about the drug's safety to worry the American Diabetes Association.

Several studies now suggest the drug, which lowers blood sugar levels, may raise the risk of heart attack. Glaxo researchers rushed out an interim analysis of an ongoing study on Tuesday the company said showed no increased risk, but independent experts disagreed.

"As a result of all of this information, the American Diabetes Association strongly encourages patients taking this medication to consult with their physician as to its benefits and risks," the non-profit group, which funds diabetes research and advocacy, said in a statement.

"The Association also reminds patients, however, that they should not stop taking any prescribed medications without first discussing the issue with their health care provider."

Type-2 diabetes is caused by a combination of genetics, a rich diet and a lack of exercise.

"The most life-threatening consequences of diabetes are heart disease and stroke, which strike people with diabetes more than twice as often as they do others. If you have diabetes, it is very important to control your blood glucose, blood pressure and cholesterol levels," the group said.

Glaxo released yet another study on Wednesday it said showed the drug's safety, but other experts said they remained unconvinced. - Reuters