Calcitriol, the active form of Vitamin D3, is primarily used to regulate calcium and phosphate levels in the body, ensuring proper bone formation and mineralization. It is commonly prescribed in conditions such as chronic kidney disease, hypocalcemia, and hypoparathyroidism, where the body cannot produce sufficient active Vitamin D. By enhancing calcium absorption from the intestine and reducing calcium loss through the kidneys, calcitriol helps prevent bone disorders like rickets and osteomalacia. Additionally, it supports muscle function and immune system regulation, making it an important therapeutic agent for patients with impaired calcium metabolism.