SHORT-TERM INTRAVENOUS BISPHOSPHONATES IN PREVENTION OF POSTMENOPAUSAL BONE LOSS

This study was performed to test the efficacy of short-term intravenou s clodronate and etidronate in the prevention of postmenopausal bone l oss, Healthy postmenopausal women, exhibiting a decreasing trend in bo ne mineral density, were randomized to five groups (clodronate at dose s of 150, 300, and 600 mg; etidronate at a dose of 300 mg; and a place bo group) of 21-22 subjects, The drugs were administered intravenously three times with I-week intervals, followed by regular evaluation for up to 24 months, During the first year, 300 mg of clodronate retarded bone loss significantly in the lumbar spine and femoral neck, where s ignificant protection still persisted after 24 months, Other doses of clodronate (150 and 600 mg) were not bone protective, Etidronate (300 mg) retarded bone loss significantly in the lumbar spine up to 24 mont hs, relative to placebo, Serum concentrations of procollagen I carboxy -terminal propeptide and urinary Ca2+ and hydroxyproline excretion dec reased in all bisphosphonate groups during the first month after treat ment but the values returned later toward baseline, In the etidronate- group, serum osteocalcin concentrations also decreased significantly d uring the first 3 months of the study, Otherwise, no uniform serum res ponses to bisphosphonate-treatment were detected in circulating marker s of bone formation, alkaline phosphatase, or osteocalcin, No signific ant differences in the serum concentrations of crosslinked carboxy-ter minal telopeptide of type I collagen were detected between the groups. Patient acceptance of both bisphosphonates was excellent, and no drug -related adverse side effects were detected, These results suggest tha t frequently repeated intravenous treatment with bisphosphonates may e ffectively counteract postmenopausal bone loss.