Bisphosphonates are a class of drug used to treat osteoperosis. They work by inhibiting the process that causes bone to dissolve, therefore strengthening the bone. Increased bone density is often a positive result. Bisphosphonates are also used to treat other diseases, such as osteopenia and Paget’s disease. Although bisphosphonates can be helpful, they are not always safe when taken long term.
The Risks of Using Fosamax Long Term
Bisphosphonates, especially fosamax, can cause non traumatic femur
fractures if taken for an extended period of time. Fosamax, known
generically as Alendronate, is usually taken in tablet or liquid form,
either daily or once weekly. There are several case reports of atypical
femur fractures, specifically subtrochanteric and diaphyseal femur
fractures, in patients taking fosamax for over five years.
How Fosamax Causes Femoral Fractures
Fosamax seems to cause these fractures by supressing bone turnover. Bone
turnover is the process in which the body removes old bone tissue and
forms new tissue to take its place. The body typically replaces 10
percent of its bone tissue each year. When this process is inhibited, as
it is with fosamax, it results in an accumulation of microdamage to the
bone. This results in the atypical femur fractures seen in patients
with a history of chronic fosamax use.
Evidence That Fosamax is Indeed the Cause of These Fractures
In 2010, the Fracture Intervention Trial and HORIZON Pivotal Fracture
Trial Steering Committees did a secondary analysis of three large drug
trials on bisphosphonates and found an increased risk for developing
femur fractures in patients taking bisphosphonates long term. Analysis
of case reports done in 2007 and 2009 confirm the correlation between
fosamax and subtrochanteric and diaphyseal femur fractures. In October
2010, the FDA added subtrochanteric and diaphyseal femur fractures to
the “warnings and precautions” section of the Fosamax label and required
that all patients be given a medication guide for this medicine. The
FDA also reccommends discontinuation of Fosamax if a femur fracture
occurs
Those Most at Risk of Developing Fosmax Induced Femur Fractures
Case studies indicate that women over the age of 60 are most at risk of
developing femur fractures, as are patients taking Fosamax for over five
years. Risk also increases with dosage so those on a higher dose of
Fosamax are more likely to develop these fractures.
Symptoms of Fosamax Induced Femur Fractures
The most common symptom , experienced by 76 percent of patients, is pain
in the thigh for months before the fracture. The fractures typically
occur with no or very minimal trauma. The break is usually a simple
transverse fracture with a unicortical beak in an area of cortical
hypertrophy. This fracture pattern is unique to Fosamax induced femur
fractures. Fractures will also be abnormally slow healing due to
Fosamax’s effect on bone turnover.
What Your Doctor Didn’t Tell You
Studies indicate that there is no increased benefit from staying on
Fosamax for longer than five years. This means that there is no reason
for a patient to stay on Fosamax after five years, especially with the
increased risk of femur fracture. In fact, most bone specialists,
however, are now recommending that Fosamax be stopped after five years,
even if the patient hasn’t yet had a fracture.
References
–J Bone Joint Surg Am. 2009 Nov;91(11):2556-61.; Bilateral low-energy
simultaneous or sequential femoral fractures in patients on long-term
alendronate therapy; Capeci CM, Tejwani NC.
–Bisphosphonates and low-impact femoral fractures: Current evidence on alendronate-fracture risk; Jennifer P. Schneider,MD, PhD
–Hong Kong Med J Vol 13 No 6 December 2007; Sequential non-traumatic
femoral shaft fractures in a patient on long-term alendronate; Ralph KH
Cheung, et al.
–Osteoporosis International Volume 22, Number 2, 373-390, DOI:
10.1007/s00198-010-1453-5; Subtrochanteric fractures after long-term
treatment with bisphosphonates: a European Society on Clinical and
Economic Aspects of Osteoporosis and Osteoarthritis, and International
Osteoporosis Foundation Working Group Report; R. Rizzoli, et al.
–Journal of Bone and Mineral Research, 25: 2267–2294. doi:
10.1002/jbmr.253; 2010; Atypical subtrochanteric and diaphyseal femoral
fractures: Report of a task force of the american society for bone and
mineral Research.; Shane, E., et al.
–PubMed Health: Alendronate
–Medscape Medical News: FDA Adds Femur Fracture Warning to Bisphosphonate Labels
