FOSAMAX (alendronate sodium) is a bisphosphonate that acts as a specific inhibitor of osteoclastmediated bone resorption. Bisphosphonates are synthetic analogs of pyrophosphate that bind to the hydroxyapatite found in bone.

FOSAMAX PLUS D (alendronate sodium & cholecalciferol) contains alendronate sodium, a bisphosphonate, and cholecalciferol (vitamin D3).