EFFICACY AND SAFETY OF DRUGS FOR PAGETS-DISEASE OF BONE

Paget's disease of bone is characterized by an anarchic bone turnover starting with excessive resorption caused by structural and functional abnormalities involving osteoclasts, Calcitonin and bisphosphonates a re now considered as the main therapeutic approaches for this disease, Daily parenteral administration of calcitonin to patients with Paget' s disease of bone results in a significant fail in serum alkaline phos phatase and urinary hydroxyproline levels. This treatment has also bee n reported to be effective in relieving clinical symptoms of the disea se, mainly bone pain, The drawbacks of injectable calcitonin have stim ulated interest in alternative routes of delivery. Substantial evidenc e of calcitonin bioavailability and bioefficacy equivalent to those of parenteral administration is currently available for only two alterna tive routes: nasal spray and rectal suppository, Since many results ha ve been published showing a dramatic effect of several bisphosphonates in Paget's disease of bone, nasal and rectal calcitonin are no longer considered as the treatments of choice in this condition, A major adv antage of the use of bisphosphonates over calcitonin in Paget's diseas e is that biochemical and histologic suppression of disease activity m ay persist for many years after the cessation of treatment, Oral etidr onate and intravenous pamidronate have been extensively used and have provided satisfactory benefits to the patient, Since the risk/benefit ratio of alendronate does not appear to be completely positive, it is likely that the future of treatment of Paget's disease of bone will be based on the oral formulation of the new bisphosphonates, including t iludronate, risedronate or dimethyl-pamidronate.