American Board of Internal Medicine (ABIM) Certification Practice Exam

What serious side effect is associated with denosumab treatment?

1. Hypertension

2. Hyperkalemia

3. Hypocalcemia

4. Thrombocytopenia

The correct answer is: Hypocalcemia

Denosumab is a monoclonal antibody that inhibits RANKL (Receptor Activator of Nuclear factor Kappa-Β Ligand), which plays a crucial role in osteoclast formation, function, and survival. By inhibiting this pathway, denosumab is effective in treating conditions like osteoporosis and certain cancers associated with bone loss. A significant side effect associated with denosumab treatment is hypocalcemia, characterized by abnormally low levels of calcium in the blood. The risk of hypocalcemia stems from the drug’s mechanism of action. Because denosumab decreases the activity of osteoclasts, which are responsible for bone resorption, it can lead to a decrease in calcium release from the bones into the bloodstream. Additionally, denosumab can hinder the body’s ability to increase calcium levels effectively during periods of low calcium, particularly if the patient is already vitamin D deficient or has underlying kidney issues. Therefore, monitoring calcium levels, especially after the initiation of therapy, is essential to prevent symptomatic hypocalcemia, which can manifest as muscle spasms, tingling sensations, and more severe complications if not addressed. In contrast, the other potential options like hypertension, hyperkalemia, and thrombocytopenia are not commonly associated