Alendronate is a bisphosphonate drug used for osteoporosis and several other bone diseases. It is marketed alone as well as in combination with vitamin D. It is used for Prophylaxis and treatment of female osteoporosis. It is also used in the Treatment of male osteoporosis, Prevention and treatment of corticosteroid-associated osteoporosis together with supplements of calcium and vitamin D and Paget's disease. Alendronate inhibits osteoclast-mediated bone-resorption. Like all bisphosphonates it is chemically related to inorganic pyrophosphate, the endogenous regulator of bone turnover. Under therapy normal bone tissue develops, and alendronate is deposited in the bone-matrix in pharmacologically inactive form. For optimal action enough calcium and vitamin D are needed in the body in order to promote normal bone development.