Fosamax Causes Fractures

Vancouver, WALong-term use of the controversial osteoporosis medication Fosamax is ringing more alarm bells with bone experts. Why? Something called spontaneous non-spinal fractures. As if osteonecrosis of the jaw and a risk of stroke weren't enough, a series of case reports published in medical literature shows a clear association between Fosamax and this type of fracture, also called atypical low-energy fractures.

It seems that the longer you take Fosamax, the higher your risk for a spontaneous fracture becomes: the cases that are known occurred in women who had been taking the bisphosphonate for more than 5 years.

Ironically, physicians have expressed safety concerns about the long-term use of Fosamax since it first arrived on the market a decade ago, because nobody knew what the long-term effects of taking this drug would be. It now appears there are problems. No surprise there.

The fractures reported in the case studies, which were published in the May/June (2008) Journal of Orthopaedic Trauma, occurred in the large thighbone that connects to the hip—the femur. According to the reports, people who suffered the fractures had felt their thighbones aching for no apparent reason, weeks or months in advance of the fractures occurring. Their thighbones literally broke spontaneously, as the people were walking or standing. And, 19 of the 20 people in the case series had been taking Fosamax for an average of 7 years.

The obvious irony is that Fosamax is prescribed to prevent fractures. And this is where the root of the problem lies. Fosamax, as with other oral bisphosphonates, is typically prescribed for periods far longer than 5 years, and in some cases, the rest of a person's lifetime. The idea being that the medication provides a lifetime of, or at the very least, prolonged protection against, fractures.

Because the clinical trials performed by Merck on Fosamax for the FDA only ran for between 3 and 5 years, atypical low-energy fractures did not emerge as a side effect.

Equally alarming is the fact that this phenomenon has been reported in the medical literature before. In 2005, a series of 9 case reports was published in the Journal of Clinical Endocrinology & Metabolism. The women in the case reports had all sustained spontaneous non-spinal fractures while taking Fosamax. Worse still, the fractures in 6 of the 9 women took anywhere from 3 months to 2 years to heal. Additional reports in the Journal of Bone and Joint Surgery cited the same early warning signs for spontaneous non-spinal fractures in women in Singapore who were taking Fosamax.

In addition to the case series, there are clinical data that show that fracture rates in women who continued taking Fosamax after 5 years are as high as those in women who stopped taking the drug at 5 years. This, from the researchers involved in the FLEX trial, published in 2006 in the Journal of the American Medical Association:

"Despite the difference in bone density during the last 5 years, the women who discontinued alendronate had essentially the same number of fractures as the women who kept taking the drug."

One theory is that after many years of using the drug, the bone actually becomes quite brittle, or is no longer able to repair damage. Regardless, if this risk was known in 2006, why was it not more widely publicized, and women warned in advance? And why is it even being prescribed beyond 5 years, given the risks and apparent lack of benefit?
Given the more frequent reports of spontaneous fractures, some osteoporosis experts are now advising that Fosamax not be taken for more than 5 years. But what about family doctors, who also write prescriptions for Fosamax?

One final note: while all the published case reports involve Fosamax, it is possible that this could be a class effect seen with all oral bisphosphonates, and not just Fosamax. Unfortunately, only time and more preventable fractures will tell.