What is the rationale for denosumab therapy and what monitoring is needed?

• A. Denosumab inhibits RANKL to reduce bone resorption; monitor calcium levels and watch for hypocalcemia, especially with vitamin D deficiency; plan for transition if stopping
• B. Denosumab stimulates osteoblast activity; monitor alkaline phosphatase
• C. Denosumab increases calcium absorption in the gut; monitor liver enzymes
• D. Denosumab acts as a calcium supplement; monitor serum calcium only

Answer: (D)

Denosumab works by binding RANKL, preventing it from activating osteoclasts. This stops osteoclast formation and activity, so bone resorption decreases and bone density improves, which helps reduce fracture risk in osteoporosis. The key monitoring concern is calcium. Because blocking resorption can lower serum calcium, check calcium levels after starting therapy and correct any vitamin D deficiency to reduce the risk of hypocalcemia. Plan for supplementation with calcium and vitamin D as needed, and be mindful of stopping denosumab because there can be a rebound increase in bone turnover and a risk of hypocalcemia—so a transition strategy to another antiresorptive is often necessary. The other statements misstate how denosumab works (it does not stimulate osteoblasts or act as a calcium supplement) and what needs monitoring (it’s not simply about alkaline phosphatase or liver enzymes).