Use of etidronate (EHDP) in Paget's disease of bone.

Etidronate used in recommended doses (usually 5 mg/kg/day for 6 months) produces symptomatic improvement in approximately 60% of patients. The serum alkaline phosphatase and urinary hydroxyproline are reduced to about 50% of initial values. A sustained remission occurs in many patients and retreatment is usually effective upon relapse. The abnormally elevated osteoclast count and resorption surfaces are reduced, and at the low dose there is no accumulation of osteoid. The medication is generally well tolerated and at the recommended dosage there is no evidence of increased fracture rate.