A 70-year-old woman with established osteoporosis (T-score −3.2) has sustained two vertebral fractures in the past 2 years despite taking alendronate 70 mg weekly for 3 years. Her bone turnover markers remain elevated. The most appropriate next pharmacological intervention is:
- A Switch to risedronate or zoledronic acid (another bisphosphonate)
- B Teriparatide (PTH 1-34) or romosozumab for anabolic bone building ✓
- C Add calcitonin nasal spray for additional antiresorptive effect
- D High-dose calcium and vitamin D supplementation as primary treatment change
Explanation
Failure of bisphosphonate therapy (two incident fractures despite adequate bisphosphonate treatment for 3 years with elevated bone turnover markers) is an indication for anabolic therapy. Teriparatide (recombinant PTH 1-34) stimulates osteoblast activity and new bone formation, significantly reducing vertebral fracture risk. Romosozumab (anti-sclerostin monoclonal antibody) simultaneously stimulates bone formation and reduces resorption (dual mechanism). Both are superior to switching between bisphosphonates in non-responders with multiple fractures. After completing anabolic therapy course (12–18 months for romosozumab, 24 months for teriparatide), consolidation with antiresorptive therapy is required.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
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Written and medically reviewed by the StethoPrep medical team.