The effectiveness of cyclic and continuous oral clodronate therapy on bonedensity and markers in osteopenic postmenopausal women

Bisphosphonates have been used effectively to treat established osteoporosi s and prevent postmenopausal bone loss. However, the optimal manner of its administration-whether cyclic or continuous-has not been well established. This study investigated the efficacy of cyclic and continuous oral administ ration of clodronate in 54 newly identified osteopenic postmenopausal women in a randomized, double-blind, crossover fashion. The participants were ra ndomly separated into two groups. The cyclic group (n = 29) received 800 mg twice daily of oral clodronate for 2 weeks every 3 months for the first 12 months followed by placebo for the second 12 months. The continuous group (n = 25) received placebo in the first 12 months and ingested 400 mg of clo dronate once daily for the second 12 months. The urinary amino-terminal (NT X(TM)) and carboxy-terminal (CrossLaps(TM)) cross-linked fragments of type I collagen, both markers of bone resorption, showed a marked decrease (25-5 0%) with both regimens during the period of active treatment. In the cyclic group, the levels of these two markers increased in the second 12 months w ith placebo, but did not return to the baseline completely. However, bone m ineral density (BMD), determined by dual-energy X-ray absorptiometry (DXA), showed no significant change of BMD at various sites after 1 year of activ e treatment in both groups. Thoracic and lumbar spine X-ray showed no new v ertebral fracture in either group after 2 years of treatment. With the two treatment protocols in this study, oral clodronate was effective in decreas ing postmenopausal bone resorption, causing no significant changes in BMD a t various sites.