The findings of new research suggest bone-strengthening drugs like Fosamax appear to lose benefits and effectiveness after about seven years of use, which may result in users being exposed to unnecessary side effects following longer-term use.
In a study published last week in the medical journal JAMA Network Open, researchers with Kaiser Permanente report a class of drugs known as bisphosphonates, which include Fosamax, Actonel, Boniva and Reclast, were less effective after seven years, and provided no benefit at all after 10 years use.
Fosamax and other bisphosphonates are widely used treatments among individuals with osteoporosis, and are intended to strengthen bones and reduce the risk of fractures associated with the medications. However, the medications have been linked to several potentially serious side effects, including atypical bone fractures which may occur with no trauma at all, as well as a painful and debilitating condition known as osteonecrosis of the jaw, involving deterioration of the jaw bone.
In this latest study, researchers looked at nearly 30,000 women who took the drug for five years, seven years and 10 years. The women were patients in Kaiser Permanente in northern and southern California, and had completed five years of treatment between January 1, 2002, and September 30, 2014. All of the subjects discontinued biphosphate use for six months, then continued for another two years or five years; after which researchers looked for those who had suffered hip fractures.
Out of the 29,685 subjects, 507 hip fracture incidents were identified. Those who continued taking the drugs for an additional two years saw a decrease in hip fracture risks, with 2.2 fewer women per 1,000 developing hip fractures after the initial five years of use. However, women who took the drugs for 10 years saw no further reduction, and the results were statistically insignificant compared to only five years of use.
“In this study of women treated with bisphosphonate for 5 years, hip fracture risk did not differ if they discontinued treatment compared with continuing treatment for 5 additional years,” the researchers concluded. “If women continued for 2 additional years and then discontinued, their risk appeared lower than continuing for 5 additional years. Discontinuation at other times and fracture rates during intervening years should be further studied.”