Consumer group Public Citizen on Thursday asked the Food and Drug Administration to ban GlaxoSmithKline PLC’s diabetes drug Avandia over fears that the drug might cause liver failure.

After eight years on the market, the world’s best-selling diabetes pill last year was linked to heart attacks. The FDA requested a black box warning about the increased risk of heart attack in November 2007. The drug continues to be prescribed to diabetics to lower blood sugar, the main goal of drugs for type 2 diabetes because the FDA concluded the inherent risk of heart attack wasn’t any greater than that associated with other similar medications. The health agency also asked Glaxo to study the issue but results from that trial aren’t expected until 2014.

Now the Washington, D.C.-based group Public Citizen claims that Avandia, also known as rosiglitazone, can cause death from liver failure and that the drug has other life-threatening risks. The organization says it has identified 14 cases of Avandia-related liver failure, including 12 deaths.

“The scientific consensus against Avandia is overwhelming. The timing of these findings should give the FDA the momentum it needs to act swiftly to prevent further needless deaths and health damage by banning this drug,” Dr. Sidney Wolfe, director of Public Citizen’s Health Research Group, said in a statement, appearing in the current issue of Diabetes Care.

Avandia was the world’s best selling diabetes drug and London-based Glaxo’s second-biggest drug in 2006, gaining the company $3.3 billion that year. The sales have fallen by more than half in the US since the heart risks were first reported. Also the number of people taking the drug declined from a peak of 13.2 million in 2006 to 4.6 million for the last full year, meaning that about 10,000 prescriptions a day are still being filled for the drug, Public Citizen said.

The number could be higher keeping in mind that obesity rates are also soaring. According to a study released today by US Centers for Disease Control and Prevention the rate of new cases of diabetes almost doubled in the US in the past ten years from 4.8 per 1,000 people from 1995 to 1997 to 9.1 per 1,000 people from 2005 to 2007. The rate is higher in the South, about 11 cases per 1,000, a region also known for high rates of obesity and lack of physical activity among its inhabitants, two main factors contributing to diabetes.

Liver toxicity is the latest problem linked to Avandia. According to the consumer group, the drug increases the risk of heart attack by 40 percent, doubles the risk of heart failure and bone fractures, increases the risk of anemia and vision loss from macular edema. These risks were too many to allow marketing of the drug to continue in the US, especially when other, safer treatments are available, the petition said.

Rita Chappelle, an FDA representative, said the agency will review the petition and respond.

On the other hand, GlaxoSmithKline stands by its drug supporting its safety and efficacy based on results of one of the largest clinical trial programs ever undertaken for any medicine, including 52,000 patients. Along with diet and exercise, Avandia helps improve blood sugar control in adults with type 2 diabetes.