RATIONALE FOR THE USE OF CLODRONATE IN OSTEOPOROSIS

Bisphosphonates are widely used in disorders associated with increased resorption of bone, particularly in Paget's disease of bone and in th e hypercalcemia of malignancy. Because of their undoubted efficacy and relatively low toxicity, bisphosphonates are attractive candidates fo r the management of osteoporosis. Clodronate, one of the many bisphosp honates being tested in osteoporosis, may be given intravenously or by mouth. In contrast to etidronate, even high doses of clodronate do no t impair the mineralization of bone, making it suitable for long-term use in osteoporosis. As do all the bisphosphonates tested thus far, cl odronate appears to delay the rate of bone loss in osteoporosis. Long- term studies are relatively few, so that its steady-state effects on b one mass are not yet known. Most data suggest clodronate is capable at least of delaying the rate of bone loss, but several pilot studies wi th this agent suggest that increments of bone mass might be sustainabl e for several years. Clodronate is likely to decrease the frequency of osteoporotic fractures, but there is no evidence for this at present. Well-controlled, long-term prospective studies are needed.