Abstract: Objective To assess the efficacy and tolerance of infusions of ibandronate on Beijing postmenopausal osteoporotic women. Methods A randomized study among 60 postmenopausal women receiving either 2-hour infusions of ibandronate(2mg) in every three months or oral 70mg/week alendronate during one year. The bone mineral density (BMD, by DXA), serum carboxy-telopeptide cross-links of type I collagen(CTX, by chemiluminescence) and alkaline phosphatase (ALP，by autonomic analysor) were measured to evaluate the efficacy. The side effects, liver and kidney function were observed to assess the tolerability. Results: 59 patients completed the observation. After one year of treatment, at the sites of lumbar spine, femoral neck and trochanter, ibandronate increased the BMD by 6.3%, 2.5% and 0.1% (lumbar P <0.001，femoral neck P <0.01), and alendronate changed the BMD by 3.7%, 4.9%, -0.5% respectively(lumbar and femoral neck, P <0.001). There were no significant differences of BMD between two groups after treatment. In ibandronate and alendronate group, ALP levels were decreased by 15.8% and 17.2%，CTX levels decline by 78.1% and 43.2%( P <0.001). The liver and kidney function were in normal range. Mild muscle pain and fever in the first month after infusion (26.7%) was the main side effects of ibandronate. Mild upper GI effect(13.3%) was the common effect of alendronate. Conclusions Intermittent infusions of ibandronate significantly increased BMD and inhibited bone resorption with good tolerance in postmenopausal osteoporotic women.

Key words: Osteoporosis, ibandronate, alendronate