Calcium-sensing receptor antagonists, also known as calcilytics, are specialized compounds that inhibit the calcium-sensing receptor (CaSR) on parathyroid chief cells and other tissues. By blocking CaSR activation, these antagonists mimic a state of low extracellular calcium, thereby stimulating the secretion of parathyroid hormone (PTH). This transient increase in PTH is beneficial for treating hypoparathyroidism, where insufficient PTH leads to hypocalcemia and related symptoms. They are also under investigation for osteoporosis and other bone disorders, as intermittent PTH elevation can promote bone formation without the sustained effects of direct PTH analogs. Unlike calcimimetics (CaSR agonists) used to suppress PTH in hyperparathyroidism, calcilytics provide an oral alternative for conditions requiring PTH stimulation, aiding in calcium homeostasis and mineral metabolism.