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Bisphosphonate osteoporosis drugs (Aclasta, Actonel, Didrocal, Fosamax, Fosavance): Small but increased risk of unusual thigh bone fractures

Starting date:
December 19, 2011
Posting date:
December 19, 2011
Type of communication:
Information Update
Source of recall:
Health Canada
Product Safety
General Public
Identification number:

Health Canada is updating Canadians with respect to its safety review of bisphosphonate drugs, used to treat osteoporosis, and the risk of a rare but serious type of thigh bone fracture known as an "atypical femur fracture."

Atypical femur fractures are very uncommon; they appear to account for less than 1% of all hip and femur fractures overall. Health Canada's review of the evidence has shown a slightly increased risk of this type of fracture with bisphosphonate use.

Although the risk is higher with bisphosphonate use, it is still extremely small. The benefits of using bisphosphonate drugs in preventing fractures associated with osteoporosis outweigh the risk of an atypical femur fracture.

Bisphosphonates are prescription drugs used to treat osteoporosis in men and post-menopausal women. They can also be used to prevent osteoporosis in post-menopausal women and in patients taking glucocorticoids. Osteoporosis is a loss of bone density often associated with aging that can cause painful fractures, disability and deformity. Bisphosphonates have a long history of effective use in osteoporosis treatment and prevention.

The product information for brand name bisphosphonate drugs has been updated with new warnings and precautions regarding this risk, including signs of a possible atypical femur fracture that patients and health professionals should watch for. Updates to the labels for generic drugs will follow. (See below for a list of bisphosphonate drugs in Canada.)

An atypical femur fracture can occur with minimal or no impact to the thigh area, and can occur in both legs in the same person. Signs of a potential fracture are dull, aching pain in the thigh, hip or groin area. A partial fracture could take weeks or months to become a complete fracture.

Patients who are currently taking or who have taken a bisphosphonate drug in the past, and who notice new or unusual pain in the hip, groin or thigh should talk to their healthcare professional as this may be a sign of an atypical femur fracture. Patients should not stop taking their bisphosphonate drug unless on the advice of their healthcare professional. Health Canada recommends that consumers should consult with their healthcare practitioner with any questions or concerns regarding the use of these products.

Healthcare professionals should be aware of the possible risk of atypical femur fractures in patients taking bisphosphonates. As noted in the updated product information, healthcare professionals should evaluate patients who report new hip, thigh or groin pain to rule out a partial femur fracture. Patients with an atypical femur fracture should also be assessed for possible signs of fracture in the other leg.

Discontinuation of bisphosphonate therapy should be considered pending an assessment of the patient or the risk/benefit of using it. Health professionals are reminded that the need for continued bisphosphonate therapy should be periodically re-evaluated.

Drug labels, or "Product Monographs," contain important prescribing and safety information for healthcare professionals and patients, and are available by searching Health Canada's Drug Product Database.

How to report side effects to health products

To report suspected adverse reaction with these or other health products, please contact Health Canada's Canada Vigilance Program toll-free at 1-866-234-2345, or complete a Canada Vigilance Reporting Form and send to us using one of these methods:

Bisphosphonate osteoporosis drugs currently marketed in Canada

Bisphosphonates drugs are available in varying strengths and dosages, and come as a liquid or tablet for oral use, or as a solution for injection.

List of bisphosphonate drugs in Canada.
Brand Name Generic Name Active Ingredient
Fosamax Fosavance Alendronate alendronate
Alendronate FC
Jamp-Alendronate FC
Pro-Alendronate FC
Riva Alendronate
Didrocal Apo-Etidronate etidronate
Co Etidrocal
Co Etidronate
Mylan-Eti-Cal Carepac
NTP-Etidronate Calcium
Actonel Plus Calcium
Actonel DR
Actonel Sachet Kit
Apo-risedronatee risedronate
CO Risedrocal Combo Kit
CO Risedronate
Mylan Risedronate
pms-risedronate plus Calcium
Sandoz risedronate
Teva risedronat
Aclasta   zoledronic acid


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