Evaluation of sodium etidronate in the treatment of Paget's disease of bone. Osteitis deformans.

Thirteen cases of advanced Paget's Disease of bone were treated with Sodium Etidronate (EHDP) at 20 mg/kg/day for 6 months and followed at 2 to 3-month intervals for 20 months with serum alkaline phosphatase, 24-hour urinary hydroxyproline, radiographic skeletal survey, whole-body scanning with Tc-99m-Sn-EHDP and F-18, external body counting with the same radiopharmaceuticals over preselected areas, skin temperature, densitometry of normal phalanges and bone biopsies. Sodium etidronate had a marked effect on Pagetoid bone in all cases with reduction of bone turnover demonstrated by the chemistries, scanning, external counting, skin temperature and X-ray diffraction studies of the bone biopsies. Normal bone did not appear to be materially affected by the drug. Complications drug dose-related included new pain in 6 cases, two fractures in Pagetoid areas and one case of severe demineralization. There was one case of spinal cord compression unlikely to be drug related. All complications cleared or were successfully treated by the end of the study. Some patients continued to show reduction in bone turnover to the end of the study, as long as 14 months after stopping EHDP. Long-term follow-up is needed for final evaluation of the efficacy of the drug. Sodium etidronate shows promise as an agent in the treatment of Paget's Disease. Smaller doses or shorter courses of therapy or combination of EHDP and calcitonin may be just as efficacious and may avoid complications.