April 26, 2002 -- Millions of diabetics now take the drug Avandia in an effort to lower their blood sugar. It is believed to be far safer than the first drug of its class, Rezulin, which was blamed for nearly 60 deaths due to liver failure before being pulled from the market two years ago.
Now a review conducted by Avandia manufacturer Glaxo SmithKline, offers the best evidence yet that the newer drug does not cause liver problems. Researchers analyzed the results of 22 clinical trials, involving more than 5,000 diabetes patients, and found no evidence of drug-related liver complications. The study was reported in the May issue of the American Diabetes Association publication Diabetes Care.
"Because this study involved such a large number of people, it provides fairly conclusive evidence that [Avandia] is safe to use," says lead author Harold E. Lebovitz, MD, of New York's SUNY Health Science Center at Brooklyn. Lebovitz is a paid consultant for Glaxo SmithKline.
Avandia and Actos, a similar drug made by Takeda Pharmaceuticals, are two of the most commonly prescribed treatments for type 2 diabetes. Like Rezulin, Avandia and Actos are insulin regulators belonging to a class of drugs known as glitazones. But unlike Rezulin, no deaths or serious liver injury have been reported in users of the two newer drugs.
In this study, liver function measurements were reviewed for just over 5,000 diabetes patients participating in studies of Avandia. The drug was given either alone, or in combination with other insulin-regulating therapies. Lebovitz and colleagues report no evidence of liver toxicity among the patients, and many patients actually had improvement in liver function with treatment.
American Diabetes Association President Christopher D. Saudek, MD, says he is not surprised by the findings, which confirm what doctors have seen in the field with both Avandia and Actos. Both drugs hit the market in 1999, and have been prescribed to millions of patients. Saudek is professor of medicine and director of the Johns Hopkins Comprehensive Diabetes Center in Baltimore.
"This is reassuring evidence that the problems with Rezulin were specific to that drug, and are not a class effect," he tells WebMD. "These drugs are not causing liver inflammation, and they appear to be as safe as anything out there."
He says it may be time for the FDA to drop a recommendation that patients on Avandia and Actos undergo regular blood tests to measure liver function. The FDA now calls for liver testing before starting either of the drugs, followed by repeat testing every two months for a year while taking them.
"Both of these drugs appear to be safe and effective therapies for people with type 2 diabetes," he says.