Overview
Denosumab is a targeted biologic therapy (monoclonal antibody) administered via injection for the treatment of osteoporosis in postmenopausal women and men at high risk for fracture. It works differently than bisphosphonates by specifically targeting a protein to halt the formation and function of bone-resorbing cells.

Mechanism of Action
It is a fully human monoclonal antibody that binds to RANKL (Receptor Activator of Nuclear factor Kappa-B Ligand), a protein essential for the formation, function, and survival of osteoclasts (the cells that break down bone). By inhibiting RANKL, denosumab dramatically decreases bone resorption, increases bone mass and strength, and reduces fracture risk.

Dosage and Administration
For osteoporosis, it is administered as a 60 mg subcutaneous injection once every 6 months by a healthcare professional. It is crucial to maintain adequate calcium and vitamin D intake during treatment. Unlike bisphosphonates, it does not require fasting or remaining upright after administration.

Side Effects
Common side effects include back pain, pain in the extremities, musculoskeletal pain, and an increased risk of infections (such as cellulitis or respiratory tract infections). Hypocalcemia can occur, especially in patients with severe renal impairment. Rare but serious risks include osteonecrosis of the jaw and atypical femoral fractures.

Contraindications
It is strictly contraindicated in patients with pre-existing hypocalcemia, which must be corrected before starting therapy. It is also contraindicated in patients with a known clinically significant hypersensitivity to denosumab.

Pregnancy and Lactation
Denosumab can cause fetal harm and is contraindicated in women who are pregnant. It is not known whether it is excreted in human milk, so a decision should be made whether to discontinue nursing or discontinue the drug.