The Food and Drug Administration in the U.S. is following the advice of an expert panel and warning patients that a widely used group of bone-strengthening drugs are linked to thigh bone fractures.
The FDA released a statement Wednesday saying that it will require that the labelling on bisphosphonate medications, such as Fosamax, Actonel and Aclasta, be changed to warn users of the risk.
"While it is not clear whether bisphosphonates are the cause, atypical femur fractures, a rare but serious type of thigh bone fracture, have been predominantly reported in patients taking bisphosphonates," the agency said in its statement.
"The optimal duration of bisphosphonate use for osteoporosis is unknown, and the FDA is highlighting this uncertainty because these fractures may be related to use of bisphosphonates for longer than five years."
The FDA recommends that doctors should reassess the need for the drugs in patients who have taken them for longer than five years.
The labe;ling changes will affect only those bisphosphonates approved for osteoporosis. They will not apply to bisphosphonates used for Paget's disease or cancer/hypercalcemia, such as Didronel, Zometa, Skelid, and their generic products.
Bisphosphonates are popular medications, commonly prescribed to women following menopause. They work by slowing down bone's natural breakdown and turnover process. But in recent years, there has been growing concern about the connection between long-term use of the medications and unusual thigh bone fractures.
Last month, a panel of experts convened to look at the matter concluded that bisphosphonates did appear to be linked to an increased risk of thigh fractures in patients who took the drugs for five years or more.
While the panel emphasized that atypical femur fractures are very rare, representing less than one per cent of all hip and thigh fractures, they urged the FDA to add a warning about the risk on the drugs' labelling.
The task force also expressed concern about the lack of awareness of the warning signs of femur fractures.
They noted that more than half of patients with the fractures who they studied had reported groin or thigh pain for a period of weeks or months before the breaks occurred. More than a quarter of patients who experienced atypical femur fractures in one leg then experienced a break in the other leg as well.
