Used primarily in the treatment of vitamin D deficiency and related disorders, especially in patients with impaired ability to synthesize or hydroxylate vitamin D, such as those with chronic kidney disease or liver dysfunction. It serves as a direct replacement therapy because it is the prehormone form of calcitriol, the active form of vitamin D. This allows for more predictable serum levels compared to cholecalciferol or ergocalciferol. Commonly prescribed to manage secondary hyperparathyroidism in chronic kidney disease patients. Also used in the management of osteoporosis and metabolic bone diseases by improving calcium absorption and bone mineralization. Due to its faster onset of action, it is beneficial in cases requiring rapid correction of vitamin D status.