Bisphosphonates are the most common class of drugs used for the treatment of osteoporosis because of their demonstrated effect on fracture reduction but the incidence of microcracks - small cracks in the skeleton - has been shown to increase with bisphosphonate treatment. This has led to some concerns regarding the potential long-term adverse effects of these agents. The new study conducted at the Indiana University School of Medicine Department of Anatomy and Cell Biology shows that the continued use of alendronate (a bisphosphonate) is not associated with continued accumulation of microdamage.

Matt R. Allen, Ph.D., assistant research professor, and David B. Burr, Ph.D., chairman, evaluated the effects of alendronate in one-year-old female beagles. The beagles were given oral doses of alendronate at levels comparable to that employed in humans (.2 mg/kg/day) or at five times the clinical dose (1 mg/kg/day) for either one year or three years.

Researchers found there was no increase in vertebral microcracks after three years of alendronate treatment in comparison to the beagles treated for one year. These results suggest that microcrack accumulation is greatest during the early course of alendronate treatment. This is an encouraging sign for long-term safety of these drugs.; Source: Indiana University