paricalcitol + cinacalcet

Paricalcitol + cinacalcet is a combination therapy for secondary hyperparathyroidism in chronic kidney disease, pairing the vitamin D receptor activator paricalcitol with the calcimimetic cinacalcet to suppress parathyroid hormone via complementary mechanisms. Paricalcitol activates the vitamin D receptor in parathyroid cells to down-regulate PTH gene expression and synthesis, and can upregulate Klotho and calcium-sensing receptor expression, thereby inhibiting PTH secretion. Cinacalcet is an allosteric modulator of the calcium-sensing receptor that increases receptor sensitivity to extracellular calcium, reducing PTH release and often lowering serum calcium. Clinical data suggest the combination is safe and may be considered when monotherapy is insufficient or when balancing calcium/phosphate control; however, some studies report no additive efficacy on PTH versus single agents, while others report improved calcium-phosphorus control over time with the combination.