Apo-Alendronate/Vitamin D3 Mechanism of Action

Alendronate sodium: Alendronate sodium is a member of a class of non-hormonal drugs called bisphosphonates.
The alendronate sodium component of APO-ALENDRONATE / VITAMIN D₃ not only prevents the loss of bone but actually helps to rebuild bone that may have been lost and increases the bone mass. This makes bone stronger and less likely to fracture. Thus, APO-ALENDRONATE / VITAMIN D₃ reverses the progression of osteoporosis.
Cholecalciferol: Cholecalciferol is the natural form of vitamin D.
Vitamin D is an essential nutrient, required for calcium absorption and healthy bones. The main source is through exposure to sunlight, which makes vitamin D in the skin. In addition, as people age, their skin becomes less able to make vitamin D. Very few foods are natural sources of vitamin D. Some foods (for example, milk, select brands of orange juice and breakfast cereals) are fortified with vitamin D.
Too little vitamin D leads to inadequate calcium absorption and low phosphate - the minerals that make bones strong. Even if eating a diet rich in calcium or taking a calcium supplement, the body cannot absorb calcium properly unless there is enough vitamin D. Too little vitamin D may lead to bone loss and osteoporosis, and severe vitamin D deficiency may cause muscle weakness which can lead to falls, and greater risk of fracture. Vitamin D supplements reduce these risks and their consequences.