What is the duration of PTH injections in this case?

• A. Two years
• B. One year
• C. Six months
• D. Three months

Answer: (B)

PTH injections act as an anabolic boost to bone, but the benefits come from a finite treatment window. The strongest bone-building responses occur over the first several months, and gains begin to plateau as the course continues. In many osteoporosis plans, a year of teriparatide (PTH analog) is used to capture the major improvement in bone density and reduce fracture risk, then the patient switches to a maintenance therapy to preserve those gains.

Choosing a one-year duration balances getting the meaningful anabolic effect with minimizing prolonged exposure and complexity of care. Shorter durations would likely miss substantial improvement, while longer ones may offer diminishing returns and pose additional considerations. After completing a year, clinicians typically reassess bone density and fracture risk and then transition to an antiresorptive agent to maintain the gains.