Pharmacology · single question
Zoledronic acid (Zometa/Reclast) is a bisphosphonate. Its mechanism of action is:
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Correct answer: D. Inhibits osteoclast function and induces osteoclast apoptosis, reducing bone resorption
- A. Bisphosphonates are anti-resorptive, not bone-forming agents. Teriparatide (PTH analogue) stimulates osteoblasts.
- B. RANKL inhibition describes denosumab (monoclonal antibody) — not bisphosphonates.
- C. Cathepsin K inhibition describes odanacatib — a different class of anti-resorptive drug.
- D. Correct. Bisphosphonates (e.g., zoledronic acid, alendronate) bind to hydroxyapatite crystals in bone at sites of high turnover. They are internalized by osteoclasts during bone resorption, where they inhibit farnesyl diphosphate synthase (mevalonate pathway), disrupting osteoclast function and inducing osteoclast apoptosis.