Used primarily in the management of hypocalcemia, especially in patients with hypoparathyroidism. It helps increase serum calcium levels by enhancing calcium absorption in the intestines and promoting bone resorption. Commonly prescribed when vitamin D is ineffective due to metabolic defects. Also used in the treatment of refractory rickets and renal osteodystrophy. Its activity resembles that of active vitamin D metabolites, making it useful in patients with impaired vitamin D activation.