Fosamax (alendronate) is one of several medications known as bisphosphonates. They are primarily used to treat osteoporosis, or thin bones. Fosamax came on the market about 10 years ago. Therefore, there are only limited studies looking its long-term use.
We do know that for people with osteoporosis, taking Fosamax for at least five years can improve the strength of the bones. Treatment for five years also has been shown to decrease the risk of breaking a bone (bone fracture). This is the reason to take the drug – because osteoporosis increases the risk of having a bone fracture. However, there is much less information available about taking the medicine for longer than five years.
There was a large study about this published several years ago in the New England Journal of Medicine. It showed that the bone density continued to improve in people who took Fosamax for 10 years. People who stopped Fosamax had a gradual loss of bone.
Unfortunately, the study was supported by the drug company that makes Fosamax. That always makes me a little suspicious. And it did not look at how many people got bone fractures during the study period – it just looked at bone density. We really are most interested in how many people actually got bone fractures, and this study did not address that.
There was another recent study that looked at using Fosamax for different periods of time. Study subjects were women with osteoporosis. All were followed for almost 10 years. Some women took Fosamax for about 10 years; others for only five. This study then looked at how many women developed bone fractures. The results were intriguing: using Fosamax was definitely beneficial for the first five years, but after that, it did not appear to provide much protection.
There is almost no information about people who have taken the medicine for more than 10 years. Some doctors worry that drugs like Fosamax may make bones more brittle over time. No one has the answers. Experts are divided about how long someone with osteoporosis should take Fosamax. More long-term studies are needed before we know.
I suggest that you speak with your doctor about your bones, bone density test results, and your treatment options. See if you can decide on a reasonable plan despite the absence of clear answers.