About Alendronate Sodium Bisphosphonate Derivative, Bone resorption inhibitor. Mechanism of Action of Alendronate Sodium It preferentially localized to the sites of action and inhibits prenylation of GTP-binding proteins involved in cytoskeletal organization, membrane ruffling and vesicle movement. This results by osteoclasts inactivation, impaired vesicle fusion and enhanced apoptosis (bone resorption inhibition). Indications for Alendronate Sodium 1. Osteoporosis 2. Paget`s disease Interactions for Alendronate Sodium Asprin: Risks of upper GI adverse effects increased. Calcium supplements antacids: Interfere with absorption of alendronate.