Before initiating denosumab in a patient with vitamin D deficiency, what should be addressed?

• A. Start denosumab immediately without tests
• B. Ignore vitamin D and calcium status
• C. Correct vitamin D deficiency and ensure calcium sufficiency
• D. Only check kidney function

Answer: (C)

Denosumab can lower serum calcium by blocking bone resorption, so ensuring mineral safety before starting is essential. If vitamin D is deficient, calcium absorption from the gut is reduced and the body has less circulating calcium to draw on when denosumab further inhibits bone-derived calcium release. Correcting the vitamin D deficiency improves calcium absorption and helps maintain normal calcium levels once denosumab is given. Along with repletion of vitamin D, verify calcium is sufficient (often with dietary intake or supplementation) before initiating therapy. This pre-treatment step minimizes the risk of hypocalcemia after the dose and guides safe ongoing monitoring.