Two Diabetes Drugs Double Heart Failure Risk: Study

Heart failure developed in some patients taking lower doses than are commonly prescribed. The average time for heart failure to develop was 24 weeks after starting the drugs, the researchers found.

Heart failure wasn't confined to older patients. Twenty-five percent of the patients who developed heart failure were under 60. In addition, both men and women developed heart failure while taking the drugs, Singh noted.

Singh's group suspect that Avandia and Actos may boost heart failure risk by encouraging fluid retention.

Current guidelines allow the use of these drugs in patients with early-stage heart failure. "Based on our information, that may have to change," Singh said.

Singh noted that there are alternative drugs available. "Doctors should be aware of the risk," he said. "Patients who are on these drugs and start developing symptoms of heart failure should see their doctor immediately, and patients not on these drugs should look at alternatives."

One expert believes that patients taking Avandia and Actos face not only an increased risk of heart failure, but Avandia users also face a 43 percent increased risk of heart attack.

"This hazard of heart failure is pretty well known for these drugs," said Dr. Steven E. Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic. He noted that, in May, the FDA said it was going to mandate a "black box" warning about heart failure risk on the labels of these drugs.

That same month, Nissen published a paper in theNew England Journal of Medicinethat found that Avandia increased the risk of heart attack.

Since then, the controversy has continued, with both sides weighing in.

On Thursday, Mary Anne Rhyne, a spokeswoman for GlaxoSmithKline, which makes Avandia, responded to the new government review by saying the company continued to believe Avandia was safe, theTimesreported.

"Across the extensive data we have, the science shows no increase in cardiovascular death, and does not support a difference in heart attack rates between Avandia and the other most commonly prescribed oral antidiabetics," Rhyne told theTimes.

On Friday, the company's director of clinical development, Dr. Andy Zambanini, toldHealthDaythat Glaxo was "still in negotiation with the FDA about a new warning label on heart failure, and we expect to release that information soon."