[Treatment of Paget's disease with phosphonates]

A group of 22 patients with Paget's disease of bone was treated with a diphosphonate (sodium etidronate; EHDP), a stable synthetic analogue of inorganic pyrophosphate. This substance was given during 3 months at the dose of 20 mg/kg body weight per day, and proved effective by reducing the raised urinary excretion of total hydroxyproline and by lowering the concentration of serum alcaline phosphatase. It also improved the disease-related osteo-articular pain in 60% of the patients. A rise in serum phosphate under EHDP therapy is due to the increase in renal tubular reabsorption of phosphate. Bone histology showed regression of disease activity and the appearance of lamellar structure in newly formed bone. Because of a transient increase of the amount of uncalcified osteoid, it is advisable to give the diphosphonate in courses not over 3 months or at a reduced daily dose.