Which of the following is NOT classified as an antiresorptive agent?

• A. Bisphosphonates
• B. RANK Ligand Inhibitor
• C. Calcium supplements
• D. Estrogen Agonists

Answer: (C)

Calcium supplements are considered nutritional support rather than a pharmacological treatment, which is why they are not classified as antiresorptive agents. Antiresorptive agents function by inhibiting the bone resorption process, thereby slowing down or reducing bone loss, typically in conditions such as osteoporosis.

On the other hand, bisphosphonates, RANK ligand inhibitors, and estrogen agonists all serve to reduce bone resorption through specific biological mechanisms. Bisphosphonates inhibit osteoclast-mediated bone resorption, RANK ligand inhibitors block the RANK/RANKL signaling pathway crucial for osteoclast development and function, and estrogen agonists modulate osteoclast activity to help maintain bone density. In contrast, calcium supplements primarily provide the essential mineral needed for bone formation and maintenance but do not directly influence the resorption process, which is why they do not fit into the antiresorptive category.