New Worries Over Blockbuster Meds Avandia, Fosamax

By Amanda Gardner
HealthDay Reporter
Tuesday, April 29, 2008; 4:00 AM

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MONDAY, April 28 (HealthDay News) -- Avandia and Fosamax, widely prescribed drugs used to treat two common health conditions, show further evidence of being linked to adverse events.

One study finds that long-term use of thiazolidinediones -- a family of diabetes drugs that includes blockbuster Avandia -- appears to be linked with an increased risk for bone fractures.

And a second study found that Fosamax, used to prevent fractures in women with osteoporosis, may be associated with a higher risk of atrial fibrillation, a type of abnormal heart rhythm.

Both studies were published in the April 28 issue of the Archives of Internal Medicine.

Avandia (rosiglitazone) and Actos (pioglitazone), both thiazolidinediones, now account for 21 percent of all oral anti-diabetic drugs prescribed in the United States. An estimated 3.5 million or more U.S. patients take Avandia, experts say.

But in 2007, Avandia and four other drugs from the same class were given a "black box" warning, cautioning users of an increased of heart problems.

The current study, led by Dr. Christian Meier of University Hospital Basel, Switzerland, looked at links between thiazolidinediones and fracture. It was designed to ascertain whether only women were affected and where fractures were most likely to occur. The research involved 1,020 men and women aged 30 to 89 who had sustained a fracture while taking Avandia, Actos, insulin or another anti-diabetic drug.

Compared to controls, individuals taking Avandia or Actos had more than double the risk of fractures, with the risk with Actos being slightly higher than with Avandia. Drug-associated fractures were particularly common at the wrist and hip. Both men and women were at risk, and the odds for fracture tended to rise with dose of drug taken.

The odds of sustaining a fracture were heightened in patients taking Avandia or Actos for 12 to 18 months and highest in those who were on the medication for two or more years.

Other anti-diabetic drugs did not show the same effect, but thiazolidinediones have a different mechanism of action (working at the cellular level) than other drugs for type 2 diabetes.