Which osteoporosis medication is limited to two years of treatment?

• A. Romosozumab
• B. Calcitonin
• C. Parathyroid hormone (Forteo)
• D. Raloxifene

Answer: (C)

Teriparatide (parathyroid hormone) is an anabolic osteoporosis medicine that stimulates bone formation when given intermittently. Its use is limited to two years over a patient’s lifetime because animal studies showed a risk of osteosarcoma, so labeling restricts it to a total of 24 months. Other agents have different safety considerations and duration guidance: romosozumab is recommended for up to about a year due to cardiovascular safety signals; calcitonin has limited efficacy and safety concerns without a strict two-year cap; and raloxifene, a SERM, can be used longer-term in appropriate patients for vertebral fracture risk reduction and breast cancer risk reduction. So the two-year limit specifically applies to teriparatide.