Bisphosphonates and Reports of Unusual Broken Bones in the Femur (Thigh Bone)

What is the concern?

Researchers have been looking into a possible link between the use of bisphosphonate medicines, such as alendronate (Fosamax®), ibandronate (Boniva®), risedronate (Actonel®) and zoledronic acid (Reclast®) and an unusual type of broken bone in the femur (thigh bone). Bisphosphonate medicines are prescribed to reduce the risk of fractures (broken bones) in people with osteoporosis.

What do we know?

Over the past several years, there have been reports from healthcare practitioners about an unusual type of broken bone in the upper part of the femur, located below the hip. Most fractures in this region of the body occur in the hip itself and only a small proportion of all femur fractures occur below the hip. Furthermore, x-rays show that the way these bones break is very different from the way bones usually break in people who experience broken bones from osteoporosis. One of the common findings in people with this kind of break is that most of them had been taking bisphosphonate medicines, usually for more than five years. Also, many of these patients reported that they had pain in the thigh and groin area prior to the breaking of the thigh bone, which could have been present for weeks or many months. The pain might be a clue to the existence of a partial fracture called a stress fracture, which does not fully heal.

A special task force was appointed by the American Society of Bone and Mineral Research (ASBMR) to do an in depth scientific review of the available case reports and scientific research on this issue. The task force found that, although rare, the risk for this unusual type of broken bone appears to increase with longer exposure to bisphosphonates. Most of these breaks occurred in people taking the medicines for longer than five years. In the review, the scientists made clear that there is no conclusive evidence to show that bisphosphonates alone are causing the unusual breaks. However, there may be a relationship between the use of bisphosphonate medicines, particularly for five years or more. At this time, it is not possible to tell how often these femur breaks occur. More research will help us to better understand the possible connection between the use of bisphosphonates and the unusual breaks. The ASBMR task force emphasizes the value of bisphosphonate therapy in persons at high risk of broken bones from osteoporosis.

Guidance for patients

If you take bisphosphonates or are considering treatment with oral bisphosphonates you should consider the following suggestions:

• Review your medicines at least once a year with your healthcare practitioner.
• If you have been taking bisphosphonates for a while, that is five years or longer, talk with your healthcare practitioner to see if you should consider a break from the medicine or switching to a different medicine.
• If you notice any unusual symptoms while taking this medicine, especially pain in the thigh or groin area, report this problem to your healthcare practitioner right away.
• Patients may also report side effects of their medicines to the FDA by phone at 1-800-332-1088 or online at: https://www.accessdata.fda.gov/scripts/medwatch/medwatch-online.htm
• Discuss your concerns about bisphosphonates or any other medicines you take with your healthcare provider and pharmacist.

Summary

All medicines are thoroughly tested prior to approval by the Food and Drug Administration (FDA), but we continue to learn more about potential side effects after medicines are approved. Clinical trials use strict standards about who can be involved in a study. Once a medicine is FDA-approved and used in large groups of people, we can learn how the general public reacts to the medicine. This includes people who have other health conditions or are taking other medicines. Also, most clinical trials last only three years. These unusual femur breaks have not been seen within this time frame with any of the bisphosphonate medicines.

The recent findings of the ASBMR task force point out a possible link between the use of bisphosphonates, particularly for more than five years, with unusual femur breaks. However, there is no conclusive evidence at this time to show that bisphosphonates alone are causing these unusual breaks. More research will help us to better understand this potential relationship.

Health professionals should learn to recognize the warning signs of these unusual femur breaks in patients taking bisphosphonate medicines, ask patients about these symptoms at each visit and report any suspected cases to the FDA MedWatch program. Serious long-term disability and death are significant consequences of broken bones caused by osteoporosis. Bisphosphonates have been shown to reduce the risk of broken bones in individuals with osteoporosis. For this reason, NOF believes the benefits of bisphosphonate treatment in patients at high risk of osteoporotic fracture strongly outweigh the risks from treatment for most individuals. As with all medicines, the risks and benefits of treatment must be carefully considered.