Our bones thin as we age, more often in women, but also in men. Thin bones (osteoporosis) make them vulnerable to fractures. There are many ways to build bone strengthâ€”the healthiest and most natural of which is regular exercise. Adequate calcium and vitamin D intake are also essential to maintain and build bone strength.
Many women who already have osteoporosis also take bisphosphonate medicines: alendronate (Fosamax), etidronate (Didronel), ibandronate (Boniva), and risedronate (Actonel). These medicines all protect against the loss of bone density and bone strength, and most are proven to protect against fractures.
But how long should women take bisphosphonates? Should it be for as long as you live, just as people with type 1 diabetes must take insulin for life? And if you need to take them for a long time, are there risks you should be concerned aboutâ€”and is there something you can do to reduce these risks?
One of the best studied bisphosphonates is alendronate. There is no doubt that the drug builds bone strength and reduces bone fractures, when taken for five years. An excellent randomized trial of over 1,000 women published in the Journal of the American Medical Association in late 2006 showed that when alendronate is continued for another five years it builds bone strength even more, and further reduces the risk of vertebral fractures that cause pain.
These benefits were strongest for women with the thinnest bonesâ€”those women who had T scores (a measure of bone density) of -2.5 or lower at the beginning of the study. The benefits were also strong for women who had experienced a vertebral fracture in the past.
On the other hand, for women with bones that were thicker and who had not previously had vertebral fractures, the benefits of continuing on alendronate for an additional five years were less clear. One encouraging result of this study was that there were no serious adverse results from taking alendronate for 10 consecutive years.
A lot of women have been on alendronate for more than 10 years. Are there any benefits to that? To my knowledge, there are no large studies of the benefits of taking any bisphosphonate drug for more than 10 years. Without such large studies to guide us, there's no definite answer and doctors disagree about what to do. In a woman who has been taking alendronate for 10 years, who has a bone density T score higher than -2.5, and who has never had a hip or vertebral fracture, I think it would be reasonable to stop the medicine and to take repeated bone density measurements on a regular basis. If bone density starts to drop, it would be reasonable to consider re-starting treatment.
What about side effects from bisphosphonates? One side effect captured a lot media attention when it was discovered a couple of years ago: damage to the bone of the jaw. This is a rare side effect that has been seen mainly in patients with cancer who have been given high doses of bisphosphonates intravenouslyâ€”not in the typical woman with osteoporosis who takes the medicines in pill form.
There also were reports that bisphosphonates might cause two kinds of heart rhythm disordersâ€”atrial fibrillation and atrial flutter. However, a recent large study from the Netherlands found no evidence for such a risk, at least from alendronate and etidronate.
A much more common side effect is "stomach trouble" in the form of heartburn, nausea, constipation, diarrhea, which occurs in 2% to7% of patients. This side effect can often be controlled or eliminated by adjusting other medicines that may also cause stomach symptoms.
So the bottom line is that, based on the best current evidence , it makes sense that women at the highest risk for fractures continue taking bisphosphonates for at least 10 years, and probably longer.
Are you taking a bisphosphonate, such as alendronate or risedronate? Are you planning to take it forever? Let me know about your experience with these medicines.
Anthony Komaroff, M.D., is the Simcox-Clifford-Higby professor of medicine at Harvard Medical School (HMS), and editor-in-chief of Harvard Health Publications at HMS. He is a practicing senior physician and was formerly director of the Division of General Medicine at Brigham and Women's Hospital.
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