DEXA DEXA Pharmacology & Osteoporosis Treatment Monitoring 1 — Questions and Answers
Question 1: Which class of medications is most commonly prescribed as first-line pharmacotherapy for postmenopausal osteoporosis in the US?
- Bisphosphonates (e.g., alendronate, risedronate) (Correct answer)
- Selective estrogen receptor modulators (SERMs)
- Parathyroid hormone analogs (e.g., teriparatide)
- Calcitonin nasal spray
Correct answer: Bisphosphonates (e.g., alendronate, risedronate)
Bisphosphonates are the most widely used first-line agents for postmenopausal osteoporosis due to their proven fracture reduction and cost-effectiveness.
Question 2: How long should a DEXA technologist wait before performing a follow-up BMD scan to assess treatment response for a patient on bisphosphonate therapy?
- At least 1–2 years after initiating therapy (Correct answer)
- 3 months after starting therapy
- 6 months after starting therapy
- Repeat annually regardless of treatment
Correct answer: At least 1–2 years after initiating therapy
ISCD guidelines recommend waiting 1–2 years before a follow-up DEXA to detect meaningful BMD changes that exceed the LSC on bisphosphonate therapy.
Question 3: A patient's follow-up spine BMD shows a statistically significant decrease despite 2 years of bisphosphonate therapy. What does this indicate?
- Possible treatment failure, non-adherence, or secondary cause of bone loss requiring clinical evaluation (Correct answer)
- Normal expected response to bisphosphonate therapy
- The DEXA machine needs recalibration
- The patient must switch to calcium supplements only
Correct answer: Possible treatment failure, non-adherence, or secondary cause of bone loss requiring clinical evaluation
A significant BMD decrease despite therapy signals potential treatment failure, poor adherence, or an undiagnosed secondary cause of bone loss.
Question 4: Which anabolic agent used for osteoporosis treatment stimulates new bone formation by mimicking parathyroid hormone?
- Teriparatide (Forteo) (Correct answer)
- Denosumab (Prolia)
- Zoledronic acid (Reclast)
- Raloxifene (Evista)
Correct answer: Teriparatide (Forteo)
Teriparatide is a recombinant PTH(1-34) analog that activates osteoblasts to build new bone, making it an anabolic (bone-building) therapy.
Question 5: What BMD change pattern is typically seen in the lumbar spine during the first 1–2 years of teriparatide therapy?
- Significant BMD increase in the spine, often 8–13% (Correct answer)
- Modest 1–2% increase similar to bisphosphonates
- No detectable change during the first year
- Decrease followed by rebound increase
Correct answer: Significant BMD increase in the spine, often 8–13%
Teriparatide typically produces robust spine BMD gains of 8–13% over 18–24 months, significantly exceeding gains seen with antiresorptive agents.
Question 6: Denosumab (Prolia) reduces bone resorption by inhibiting which signaling molecule?
- RANK ligand (RANKL) (Correct answer)
- Interleukin-6 (IL-6)
- Sclerostin
- Calcitonin receptor
Correct answer: RANK ligand (RANKL)
Denosumab is a monoclonal antibody that binds and neutralizes RANKL, blocking osteoclast differentiation and activity.
DEXA DEXA Pharmacology & Osteoporosis Treatment Monitoring 1
Which class of medications is most commonly prescribed as first-line pharmacotherapy for postmenopausal osteoporosis in the US?