The use of bisphosphonates in the treatment of osteoporosis

Purpose of review The bisphosphonates alendronate and risedronate, given orally once weekly, are the cornerstone of treatment of postmenopausal osteoporosis, as well as of male and secondary osteoporosis. They reduce significantly the risk of vertebral and nonvertebral fractures; their effects appear early, within 6-12 months, and appear to be sustained. Several questions remain unanswered, however. In addition, data on a new bisphosphonate became available in 2004. Recent findings The optimal duration of treatment has not been clearly established. Long-term data with alendronate are now available, indicating a persistence of alendronate effects on bone mineral density and bone turnover markers several years after stopping treatment given for 5 years. Whether these effects translate into sustained reduction of fractures needs to be further analyzed. Because of their efficacy, bisphosphonate use has been explored in other forms of osteoporosis, such as after androgen deprivation therapy for prostatic cancer. The challenge of long-term compliance with treatment of osteoporosis has triggered the use of intermittent bisphosphonate. The effects of intermittent oral and intravenous ibandronate on bone mineral density, bone turnover, and fractures have been recently reported. Summary The mechanism by which bisphosphonates improve bone strength is not yet fully understood but probably involves complex effects on different components of bone strength, such as microarchitecture.