Vitamin D Deficiency Replacement — RACP Adult Medicine MCQ

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EasyEndocrinologyVitamin D Deficiency ReplacementRACP Adult Medicine

A 50-year-old woman with osteoporosis has 25-OH vitamin D of 25 nmol/L (deficient, <50 nmol/L). She has no malabsorption. Calcium is 2.15 mmol/L (low-normal). PTH is 9 pmol/L (mildly elevated, secondary hyperparathyroidism). What is the most appropriate vitamin D replacement regimen?

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Correct answer: A — Cholecalciferol 3000-5000 IU daily for 6-12 weeks then 1000 IU maintenance

Vitamin D deficiency (25-OH-D <50 nmol/L) requires loading/replacement doses before maintenance. RACGP/Osteoporosis Australia 2024: cholecalciferol 3000-5000 IU daily for 6-12 weeks until level >50 nmol/L, then maintenance 1000-2000 IU daily. The target is 25-OH-D 50-75 nmol/L. Calcitriol is NOT appropriate for vitamin D deficiency (it bypasses the regulatory step and risks hypercalcaemia). Recheck 25-OH-D at 3 months.

Reference: RACGP – 2024 – Vitamin D; Osteoporosis Australia 2024; eTG Endocrine 2024