Sustained biochemical effects of short treatment of Paget's disease of bone with dichloromethylene diphosphonate.

The relationship between duration of treatment and biochemical parameters reflecting antiosteoclastic activity was studied in 26 patients with Paget's disease of bone receiving Cl2MDP 1600 mg/day. Six months after initiation of therapy, the reduction in total urinary hydroxyproline was not different in patients treated for 1, 3, 5, or 6 months. This remission lasted 1 year for all groups. In contrast, the longest treatment induced the greatest reduction in serum alkaline phosphatase. One year after the initiation of therapy, this reduction was sustained, whereas a slight relapse was noted in other groups. From these findings, it appears that a rapid bone load with oral Cl2MDP can induce a long-lasting reduction in bone resorption excess.