Fosamax Jaw is the most feared complication of bisphosphonates, drugs commonly used to treat osteoporosis. However, failure of bisphosphonates to improve bone mineral density is common, as are fractures while on bisphosphonates. That is, bisphosphonates do not always improve your bones, and doctors are just learning now why they fail to do so.
In a study out of Weill Cornell Medical College in New York, Dr Amanda Carmel and colleagues studied failure of bisphosphonates and vitamin D levels. Based on fracture studies that indicate a 25(OH)D level of at least 33 ng/ml is needed to prevent fractures, Dr Carmel hypothesized that such a vitamin D level would be needed to allow bisphosphonates to optimally improve bone mineral density.
The authors studied 210 patients with a before and after a bone (DEXA) scan who had been on bisphosphonates for at least 18 months and who had a vitamin D level drawn. They classified patients as non-responders if they still had low bone mineral density, despite 24 months of bisphosphonates, a decrease of bone mineral density during treatment, or a new low-trauma fracture.
They found that response rates for the bisphosphonates were 66% for those with a 25(OH)D > 40 ng/ml, 50% for those with a 25(OH)D between 30 and 40 ng/ml, and only 21% for those with a 25(OH)D of <20 ng/ml. Patients with levels above 33 ng/ml had a 4.5 greater odds of a response. Almost one fourth of patients treated with a bisphosphonate suffered a low-impact fracture during the study period. They also concluded that a 1 ng/ml increase in 25(OH)D was associated with a 5% increase in the chances of responding well to bisphosphonates.
As they found that levels of 20 ng/ml (the Food and Nutrition Board’s adequate level) were clearly inadequate, they wrote, perhaps tongue in cheek, “These findings suggest that the currently accepted population standards for vitamin D repletion may not be sufficient for optimal outcomes in patients taking bisphosphonates for low bone mineral density and osteoporosis.”
Unfortunately, the authors did not seem to realize that some of their patients treated for osteoporosis probably had osteomalacia, adult rickets, although they said that a prior diagnosis of metabolic bone disease was part of the exclusionary criteria. Too often, physicians think all cases of low bone mineral density is osteoporosis. Many would only recognize a case of osteomalacia if the patient wore a sign saying “osteomalacia.”
Fosamax is also associated with a peculiar type of leg fracture that cuts straight across the upper thighbone after little or no trauma. One doctor reports that a 59-year old healthy woman visiting New York City was riding a subway train when the train jolted. She had been taking Fosamax for 7 years. She felt a bone snap and fell to the floor of the train. An x-ray revealed a spiral fracture involving the right femur, a large bone that should not fracture unless confronted with major trauma. In 2010, the Food and Drug Administration issued a warning about these kinds of fractures.
Practitioners need to diagnose and treat vitamin D deficiency before proceeding to use bisphosphonates, less they be faced with a patient whose bone scans worsen, who has an unusual facture or even Fosamax Jaw. Practitioners also need to know that Fosamax Jaw is now an instant lawsuit. Five thousand IU/day of D3 will help prevent such lawsuits.