Cyclical clodronate is effective in preventing postmenopausal bone loss: a comparative study with transcutaneous hormone replacement therapy.

An investigative study was carried out for 2 years involving 124 randomly selected early postmenopausal women with spine bone mineral density (BMD) below the mean value of a normal premenopausal subject. After random division into three groups, the first 42 patients were treated with transcutaneous 17-beta-estradiol (50 micrograms daily), the second 42 were treated with cyclical intravenous clodronate (200 mg/month iv infusion), and the third group of 40 (controls) was left untreated. After 2 years, the total drop in BMD within the control group was more than 7% as opposed to the values of -0.14% +/- 0.93 in the estradiol group and 0.67% +/- 0.84 in the clodronate group. A change in BMD of < 1% was considered satisfactory, and this result was obtained in 32% of the controls, in 79% of the estradiol group where the percentage change in BMD moderately correlated with serum estradiol levels (r = 0.399), and in 90% of the clodronate-treated patients, in whom the percentage change in BMD inversely correlated with basal values of markers of bone turnover. Both estrogen and clodronate prevent postmenopausal bone loss. The response to transcutaneous hormone replacement therapy may be influenced by transcutaneous absorption and by a lower sensitivity to estrogen. Response to cyclical clodronate seems to be influenced by the rate of bone turnover. An interdosage interval ranging from 2-4 weeks appears suitable for most patients.