[Calcitonin in the prevention and therapy of osteoporosis]

Main arguments for application of calcitonin in the therapy of osteoporosis are specific inhibition of osteoclasts, analgetic effect and stimulation of osteoblasts, the latter demonstrated only in vitro so far. Calcitonins are mostly used only for a short term in acute painful phases of osteoporosis. For salmon calcitonin, which has been tested most up to now, it has been demonstrated that its application in primary osteoporosis up to one year leads to a moderate but significant increase in bone mass. This metabolic effect on bone has been reached in the majority of studies in a combination with 500 to 1000 mg of calcium. The secondary clinical resistance observed after even longer application is presumably not so much a problem of antibodies than the consequence of depressed bone remodelling due to chronic inhibition of osteoclasts. The circulating antibodies during application of salmon calcitonin are only partially also neutralising. As to human calcitonin, therapeutic studies of corresponding length in manifest osteoporosis do not yet exist. Salmon calcitonin as nasal spray inhibits the increased postmenopausal skeleton breakdown in sound women during application of up to two years at present. In steroid-induced osteoporosis there are positive therapeutic results for both injectable and nasal calcitonin. Calcitonin therapy of osteoporosis in phases of some weeks to some months can be generally recommended nowadays. For a long-term therapeutic recommendation we still lack further studies in order to evaluate the effects of different dosage, mode of application and intermittent application.