The diabetes drug rosiglitazone, already under fire because it has been found to increase the risk of heart attacks, can also produce liver failure and death in some patients, researchers from the activist group Public Citizen said this week.

They wrote in the journal that a review of adverse events reported to the Food and Drug Administration found 11 deaths due to liver toxicity between 1997 and 2006 associated with the drug, which is sold under the brand name Avandia. The group had petitioned the FDA in October to ban the drug because of the heart risks, and they renewed their call for action.

"Because of low reporting rates to the [FDA] database, the 11 cases likely represent a small fraction of the patients who developed liver failure because of the drug," said Dr. James Floyd of Public Citizen. He estimated that 1 in every 44,000 patients who take the drug develops liver failure.

Previous studies have shown that Avandia increases the risk of heart attack by about 40%, doubles the risk of heart failure and bone fractures, and increases the risk of anemia and vision loss from macular edema, a swelling of the retina caused by the accumulation of fluids in the eye, according to Public Citizen. Reports of the drug's risk have sharply reduced prescriptions for it: They dropped from a peak of about 13.2 million in 2006 to 3.1 million in 2008. That means that 8,500 prescriptions for the drug are still filled every day.

The group also found 10 deaths from liver failure associated with the related drug pioglitazone, sold under the brand name Actos. That drug has not been linked to heart attacks, but is associated with an increased risk of heart failure, Floyd said. Public Citizen estimated 1 case of liver failure for every 52,000 patients taking it.

The manufacturers of both drugs contend that no scientific study has linked them to liver toxicity. Public Citizen, however, recommends that patients should stick to older and safer -- and, not incidentally, cheaper -- medications like metformin (Glucophage) and glipizide (Glucotrol).