Common Questions
What are long-term safety concerns regarding use of bisphosphonates?
Both bone resorption and formation are necessary to repair microarchitectural damage to bone (1). Because alendronate reduces bone resorption, there are theoretical concerns that continuous use over time might interfere with repair of microdamage and increase bone fragility, causing brittleness and increasing the risk of fracture.
A recent study found that alendronate was well tolerated over a 10-year period (2). It also found that women who had discontinued the drug after 5 years had about the same fracture rate as those that continued with it for 10 years.
Since the anti-fracture effect of alendronate occurs early on in treatment and is sustained over time even after discontinuing the drug, it seems reasonable to stop treatment at around 5 years as the safety beyond 10 years is not known.
- Frost HM. A brief review for orthopedic surgeons: Fatigue damage (microdamage) in bone (its determinants and clinical implications). J Orthop Sci 1998; 3: 272-81.
- Bone HG, Hosking D, Devogelaer JP, Tucci JR, Emkey RD, et al. Alendronate Phase III Osteoporosis Treatment Study Group. Ten years' experience with alendronate for osteoporosis in postmenopausal women. N Engl J Med 2004; 350: 1189-99.