ABSTRACT
Antiresorptive and osteoanabolic agents constitute the two major classes of antiosteoporotic medication. Antiresorptive agents are most commonly used for postmenopausal, male, and glucocorticoid-induced osteoporosis. Osteoanabolic agents, which promote bone formation by activation of osteoblasts, are used as a second-line therapeutic modality, mainly for patients with severe osteoporosis and high fracture risk, unresponsive to antiresorptive compounds. The only osteoanabolic agents for the treatment of osteoporosis approved by the U.S. Food and Drug Administration (FDA) are teriparatide, a parathyroid hormone (PTH) synthetic analogue, and abaloparatide, a PTH-related peptide synthetic analogue. Both are administered as daily subcutaneous injections and may reduce the incidence of vertebral and nonvertebral fractures. They are generally well tolerated, with headache and nausea being the most common side effects. A third agent, which is characterized by a dual mechanism of action, is romosozumab—a humanized monoclonal antibody against sclerostin. It is effective in reducing vertebral and nonvertebral fracture risk. So far, it is under evaluation by the FDA, given concerns regarding an increased risk of cardiovascular disease events. The optimal sequence of administration of antiosteoporotic agents remains a matter of debate. A common strategy needing further proof is to administer antiresorptive agents after osteoanabolic ones to consolidate bone mineral density gains.
