Which pharmacologic agent class directly inhibits osteoclast-mediated bone resorption by binding to bone mineral and inducing osteoclast apoptosis, and is commonly used as first-line therapy for many high-risk postmenopausal women?

• A. Parathyroid hormone analogs used continuously to suppress osteoclast activity and therefore are first-line for rapid antiresorptive therapy in the immediate postmenopausal years.
• B. Bisphosphonates (e.g., alendronate), because they adsorb onto hydroxyapatite, inhibit osteoclast function, and reduce bone resorption, decreasing fracture risk in high-risk postmenopausal women.
• C. High-dose vitamin C therapy that chelates excess calcium and redirects mineralization into cortical bone preferentially; this is the mainstay of pharmacologic osteoporosis treatment.
• D. Systemic corticosteroids given intermittently to stimulate osteoblast proliferation and mineral deposition, which are recommended for primary prevention of osteoporosis.

Answer: (B)