paricalcitol + cholecalciferol

**Paricalcitol + cholecalciferol** is a combination of two vitamin D analogs: **paricalcitol**, a synthetic vitamin D2 analog, and **cholecalciferol** (vitamin D3). This combination is used to treat and prevent secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD), especially those on hemodialysis. Paricalcitol acts as a selective activator of the vitamin D receptor (VDR), reducing parathyroid hormone (PTH) synthesis and secretion with a lower risk of hypercalcemia and hyperphosphatemia compared to other vitamin D agents. Cholecalciferol replenishes vitamin D stores and further suppresses PTH, providing additive benefits for PTH reduction and increasing serum 25-hydroxyvitamin D. The combination has been shown to lower PTH levels more effectively than either agent alone and maintain adequate vitamin D status, with a potential impact on innate immunity through increased cathelicidin (hCAP-18) levels[1][4][7].