New Worries Over Blockbuster Meds Avandia, Fosamax

(Page 2)

The findings echo some previous research which found an increased risk of fractures in women.

For now, the decision to use these particular diabetes drugs should be made on a case-by-case basis, experts said. Women who are postmenopausal and therefore at risk for fractures may want to be more careful, or take other measures to protect their bone health, they said.

"I think the benefit is more than the risk at this point. The benefit is huge in terms of glycemic control," said Dr. Spyros G.E. Mezitis, endocrinology consultant and clinical investigator at Lenox Hill Hospital in New York City.

"It remains to be seen if the way we practice medicine is going to change. These are important analyses, but we need further evidence," Mezitis added.

Nancy Pekarek, a spokeswoman for Avandia manufacturer GlaxoSmithKline, noted, "We do have fractures on our label and, in fact, when we saw data from the ADOPT (a previous, long-term trial), we issued a 'dear doctor' letter."

"The fractures have been observed, and we have made physicians aware of that so they can be watching for their patients and choose which drug is appropriate," Pekarek said. Unlike this trial, the fractures seen in ADOPT were more likely to be in the upper arm, hand or foot as opposed to hip and spine.

The Fosamax study, led by Dr. Susan Heckbert of the University of Washington and Group Health, Seattle, looked at 719 women with confirmed atrial fibrillation in a "real world" setting, versus 966 controls (without atrial fibrillation).

The study found that 6.5 percent of women who had used Fosamax had atrial fibrillation compared to 4.1 percent of controls. Based on these findings, the researchers estimated that 3 percent of new cases of atrial fibrillation in this group of women might be attributable to the use of Fosamax.

Again, the authors cautioned, risks and benefits should be carefully weighed when prescribing the drug.

Other studies have also reported atrial fibrillation as a side effect of bisphosphonates, the class of drugs that includes Fosamax.