Spontaneous fractures of uninvolved bones in patients with Paget's disease during unduly prolonged treatment with disodium etidronate (EHDP).

Three patients with Paget's disease of bone were treated by disodium etidronate (EHDP) without interruption during periods of 18 to 30 months. In one case the daily dose was also unduly high (approximately equal to 18 mg/kg/day). A moderate to conspicuous diminution of the renal function was observed in all cases. The three patients developed skeletal pain in a gradual but progressively severe pattern. Seven nontraumatic fractures in nonpagetic bones were encountered. EHDP produces blockage of bone mineralization and excessive suppression of bone remodeling, therefore increasing the risks of fracture. EHDP affects not only pagetic bones but normal skeleton. A baseline evaluation of the renal function might help to identify those patients with greater risk to develop skeletal side effects during EHDP treatment.