US Pharm. 2010;35(12):100. 

The FDA warned patients and health care providers about the possible risk of atypical thigh bone (femoral) fracture in patients who take bisphosphonates, used to prevent and treat osteoporosis. A labeling change and Medication Guide will reflect this risk. Bisphosphonates inhibit the loss of bone mass in patients with osteoporosis. Bisphosphonates have been shown to reduce the rate of osteoporotic fractures (fractures that can result in pain, hospitalization, and surgery) in patients with osteoporosis. 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 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 5 years. The labeling changes and Medication Guide will affect only those bisphosphonates approved for osteoporosis, including oral bisphosphonates such as Fosamax, Fosamax Plus D, Actonel, Actonel with Calcium, Boniva, Atelvia, and their generic products, as well as injectable bisphosphonates such as Reclast and Boniva.