Bone remodeling is a complex but coupled process in which old bone is resorbed, followed by the formation of new bone. Ten percent of the human skeleton is remodeled per year. Osteoporosis is a disorder of bone remodeling characterized by uncoupling of resorption from formation. The net result is a loss of bone mass. Pharmacologic agents can restore bone mass by inhibiting bone resorption or stimulating new bone formation; antiresorptive agents suppress osteoclast-mediated dissolution more than bone formation, resulting in a secondary increase in bone mineral density (BMD). This alters the remodeling sequence and strengthens bone by reducing microperforations. In turn, osteoporotic fractures of the hip and spine are reduced. At the present time, virtually all drugs, except one, that are approved by the US Food and Drug Administration (FDA) for the treatment of established osteoporosis act to inhibit bone resorption. These include calcitonin, estrogen, raloxifene (Evista; Lilly, Indianapolis, IN), risedronate, and alendronate.
KeywordsBone Mineral Density Growth Hormone Bone Mass Bone Turnover Salmon Calcitonin
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