Harvard Health Letter

By the way, doctor: Should I continue to take Fosamax?

Q. I've taken Fosamax for 11 years. My bone density has improved. One doctor I consulted told me to continue taking it, but another said it would be dangerous to do so. What should I do?

A. Alendronate (Fosamax) is a bisphosphonate, the first type of drug used by doctors to treat osteoporosis, an age-related condition that makes bone brittle and more likely to break. There's no doubt that alendronate builds bone strength and reduces bone fractures when taken for up to five years.

An excellent placebo-controlled trial of more than 1,000 women published in the Journal of the American Medical Association in 2006 showed that when alendronate is continued for another five years, it continues to build bone strength and further reduce the risk of vertebral fractures — breaks in the bones of the spine — that produce symptoms. These benefits were most pronounced for people who had T scores (a measure of bone density) of –2.5 or lower at the beginning of the study, or who had previously had a vertebral fracture. But for the women whose bones were denser at beginning of the study (T scores higher than –2.5) or who hadn't previously had vertebral fractures, the benefits of taking alendronate for an additional five years were less clear. (Keep in mind that T scores are expressed as negative numbers, so scores higher than –2.5 are –2.4, –2.3, and so on.) One encouraging result of this study was that there were no adverse results from taking alendronate for 10 consecutive years.

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