[en] Osteoporosis, associated with a high turnover of bone and acute bone loss, occurs in a number of clinical models, such as following prolonged steroid therapy, extremity and spinal immobilisation, and often is associated with fracture. Confinement to bed and subsequent hypodynamism relating to the pain following a vertebral fracture may activate the process of high bone turnover and acute bone loss. In postmenopausal women, the acute bone loss resulting from such clinical pictures may be superimposed on to the natural course of bone loss occurring in many postmenopausal women. Salmon calcitonin, a potent inhibitor of osteoclast activity, has been shown to prevent bone loss in all clinical models of acute bone loss due to increased bone turnover and osteoclastic resorption. In addition, salmon calcitonin has a potent analgesic effect, thereby causing a reduction in bone pain and improvement in functional capacity. For these reasons, calcitonin remains a first-line therapy in bone loss related to a hyper-resorptive state.