Fosomax and Osteonecrosis
Fosomax (which is also called aldrenoate) is an example of a group of medications called bisphosphonates. Bisphosophonates are used to treat metastatic cancers as well as to help control osteoporosis. However, long-term use of bisphosphonates has now been linked to a jaw condition known as osteonecrosis. Osteonecrosis occurs when the cells of the bone die off and can be particularly difficult to treat in the jaw. There have been a series of class-action lawsuits against the makers of Fosomax because of its failure to warn patients and physicians of this debilitating potential side effect. This side effect has been especially rampant in patients receiving long-term administration of Fosomax to treat cancer.
Osteonecrosis Symptoms
Osteonecrosis can occur for many months without any symptoms being present (aside from exposed bone within the jaw). Often osteonecrosis, when it is related to bisphosphanates, will occur after dental work has been done, such as the removal of teeth. However, osteonecrosis can also occur as a result of bisphosphanate treatment with no other triggers. Early symptoms of osteonecrosis include jaw pain and a sudden decrease in the overall health of teeth and gums. Tooth and mouth pain are also common, as well as a failure of the gums to heal after relatively minor trauma. Any feelings of localized burning or tingling within the jaw may also signal osteonecrosis. Repeated infections of the mouth and gums, or the sudden loosening or falling out of teeth may also occur. The final (and hallmark) symptom of jaw necrosis is exposed bone (from the jaw) appearing inside of the mouth.
Mechanism
One of the reasons why osteonecrosis tends to occur primarily in the jaw is that the jaw receives more blood flow than many other bones, which allows the medication to accumulate in this area. According to a study published in 2006 that was overseen by Dr. Kalmar at Brigham and Women's Hospital and the Harvard School of Dental Medicine, bisphosphanates may lead to osteonecrosis by preventing the natural turnover of bone cells. Bisphosphonates prevent the action of osteoclasts, which are responsible for breaking down bone matrix (the main structural building block of bones). When the osteoclasts are no longer functioning, it prevents certain chemical signals from going out which stimulate the growth of new bone-forming cells (known as osteoblasts). As a result, over time the cells within the bone die off, which then causes osteonecrosis. There is also evidence that bisphosphonates can prevent the growth of capillaries, which can also lead to a lack of circulation which can contribute to the bone death.
