Use of Etidronate in the Treatment of Postmenopausal Osteoporosis

Objective: To discuss the use of etidronate, a biphosphonate, in the treatment of women with postmenopausal osteoporosis and to determine its place in therapy when compared with conventional therapies. Data Sources: A MEDLINE search was conducted for clinical trials and review articles on biphosphonates in the treatment of osteoporosis. Study Selection: Six clinical trials and four review articles were selected because they dealt specifically with a biphosphonate in the treatment of postmenopausal osteoporosis. Data Synthesis: The studies provide a look at how the treatment evolved from continuous etidronate therapy to the more accepted intermittent cyclic therapy. The studies showed an increase in bone mass and a decrease in vertebral fractures in women receiving cyclic therapy with etidronate compared with those receiving placebo. In one study, however, a follow-up report one year later revealed that women taking etidronate experienced a 50 percent increase in vertebral fracture rate compared with those receiving placebo. This was a complete reversal from the data collected over the first two years of the study. This follow-up study is useful to point out a major potential concern associated with long-term use of etidronate—that etidronate therapy may cause mineralization defects, which could lead to alterations in bone integrity. Conclusions: Etidronate therapy has shown benefit in preserving bone in postmenopausal women. Comparative trials with conventional therapies such as estrogens have not been completed, which makes it difficult to determine etidronate's place in therapy. Long-term trials also are necessary to assess etidronate's potential to cause mineralization defects.