If severe hypercalcemia persists after hydration, which adjunct therapy may be used?

• A. Calcitonin
• B. Vitamin C
• C. Calcium carbonate
• D. Furosemide

Answer: (A)

When severe hypercalcemia persists after hydration, quick reduction of calcium levels is the goal, and calcitonin provides that rapid effect. Calcitonin lowers serum calcium by inhibiting osteoclast activity, which reduces bone resorption, and it also helps the kidneys excrete calcium more efficiently. This makes it an effective adjunct while longer-acting treatments, like IV bisphosphonates, begin to work over the next day or two. The rapid but short-lived action of calcitonin is helpful in stabilizing patients who remain hypercalcemic after fluids.

Vitamin C has no significant impact on calcium balance, so it won’t help lower calcium. Calcium carbonate would add calcium to the system, worsening hypercalcemia. Furosemide can promote calcium excretion, but it is not preferred as a routine adjunct due to risks of dehydration and electrolyte disturbances; it’s not the primary strategy for managing persistent hypercalcemia.