Study on mice suggests Avandia may lead to bone loss

LA JOLLA, Calif. In addition to the recently added black box warning regarding heart problems, Avandia may have another warning to add, as a study raises questions about the drug’s contribution to bone loss, according to published reports.

Based on a study conducted on mice, researchers are concerned that over the long term, Avandia (rosiglitazone) may speed osteoporosis, the thinning of the bones that can lead to dangerous and even fatal fractures. The findings appear in the Dec. 2 online issue of Nature Medicine.

“Our study suggests that long-term rosiglitazone usage in the treatment of type II diabetes may cause osteoporosis due to both increased bone resorption and decreased bone formation,” said study senior author Ron Evans, a professor at the Salk Institute for Biological Studies in La Jolla, Calif. “Because Avandia is effective in controlling glucose and restoring the body’s sensitivity to insulin, we do not recommend that people stop their treatment. You must balance the benefits against the complications.”

An estimated 3.5 million or more patients in the U.S. take Avandia. The drug affects a key cellular protein called the peroxisome proliferator-activated receptor. In their study, the California team discovered that, in mice, activating this receptor also stimulates the production of osteoclasts, cells whose key function is to degrade bone.

“Anyone who is already at risk for osteoporotic fractures should consider an alternative anti-diabetic drug,” added Paul Brandt, an associate professor of neuroscience and experimental therapeutics at Texas A&M Health Science Center College of Medicine. “There are many alternatives, “ he said, adding that “It may be possible to blunt some of Avandia’s effects with anti-osteoporosis drugs such as bisphosphonates, raloxifene, vitamin D and calcium.”

Avandia is produced by GlaxoSmithKine. Sales of the drug have fallen drastically since May, when the Food and Drug Administration issued a safety alert regarding the potential cardiovascular issues.