<p>Alendronate Sodium is a bisphosphonate that acts as a specific inhibitor of osteoclast mediated bone resorption. Alendronate is effective when administered at least 30 minutes before breakfast. It transiently distributes to soft tissues following administration but is then rapidly distributed to bone or excreted in the urine. Protein binding in human plasma is approximately 78%. There is no evidence that Alendronate is metabolised in animals or humans. At the cellular level, Alendronate shows preferential localization to sites of bone resorption, specially under osteoclasts. It inhibits osteoclast activity. In addition, bone formation exceeds bone resorption, leading to progressive gains in bone mass. Vitamin D is required for normal bone formation. Vitamin D insufficiency develops when both sunlight exposure and dietary intake are inadequate. Insufficiency is associated with negative calcium balance, increased parathyroid hormone levels, bone loss, and increased risk of skeletal fracture.</p>