A 42-year-old woman with osteoporosis started on alendronic acid; which monitoring requirement is most appropriate?

• A. Calcium
• B. Vitamin D
• C. Parathyroid hormone
• D. Vitamin B12

Answer: (B)

Supplying alendronic acid to treat osteoporosis works best when vitamin D levels are sufficient. Vitamin D is needed for proper calcium absorption in the gut and for bone mineralization. If vitamin D is deficient, calcium absorption drops, which can lead to low calcium levels (hypocalcemia) and may blunt the beneficial effects of the bisphosphonate on bone, as well as increase safety risks. Checking and correcting vitamin D status before and during therapy helps ensure calcium remains available for bone-building and that the drug can work effectively.

Calcium monitoring is important in many patients, but the key parameter that guides safe and effective use of an alendronate regimen is vitamin D status. Parathyroid hormone isn’t routinely tracked unless there’s a calcium or PTH disorder, and vitamin B12 isn’t related to this osteoporosis treatment.