Bisphosphonates, such as Actonel, Boniva, and Fosamax (a drug already linked to severe musculoskeletal pain and osteonecrosis – a serious bone-related jaw disease), are a widely prescribed class of drugs used to slow bone loss and prevent fractures associated with osteoporosis. In 2010 alone, an estimated 36.5 million prescriptions were dispensed for these drugs. Unfortunately, new research shows that instead of preventing fractures, use of these drugs may actually increase the risk of severe fractures in the femur.

In February 2011, a study published in the Journal of the American Medical Association found that long-term treatment with bisphosphonates increases the risk of rare femur fractures by three times compared to women prescribed a bone drug for less than 100 days. Long-term treatment in the study was defined as continuous use for more than five years.

This week, the New England Journal of Medicine published a study finding a several fold increased risk of atypical femur fractures associated with the use of bisphosphonates for less than a year of use, and a particularly high (50x) risk after 1.9 years of use. The journal analyzed data from 1.5 million women in Sweden who were 55 or older in 2008 and found that 1,271 had fractures, and out of that group, 59 had snapped thighbones.

 Although these findings suggested that these atypical fractures are somewhat rare, and that the benefits of using these drugs still outweigh their risks, health experts will continue to keep a close eye on bisphosphonates and women should be aware of the risks involved in using these drugs.