GlaxoSmithKline’s Avandia, once the world’s best-selling diabetes drug, will be withdrawn from the market in Europe and sales will be limited in the United States because of an increased risk of heart attacks, regulators said in decisions announced almost simultaneously.

Glaxo will stop promoting the drug in all countries in which it operates, the company said Thursday. Doctors should stop prescribing the treatment, the European Medicines Agency said in a statement. The London-based regulator said it found no measures that could be taken to reduce the risk.

In the United States, the drug will carry new warnings after a three-year battle that divided staff at the Food and Drug Administration. London-based Glaxo must add new cautions to Avandia’s prescribing information, the agency said Thursday. The decision to allow continued sales of the drug follows the recommendations of an FDA advisory panel in July.

“We struggled with it, and colleagues in other jurisdictions struggled as well,” Hans-Georg Eichler, the EMA’s senior medical officer, said on a conference call with reporters.

Avandia’s sales have fallen since a study published in the New England Journal of Medicine in 2007 showed a 43 percent increased risk of heart attacks from the drug. Glaxo has said “extensive clinical data” have shown the drug to be safe.

“The company continues to believe that Avandia is an important treatment for patients with Type 2 diabetes and is now working with the FDA and EMA to implement the required actions,” according to Glaxo’s statement.