Renal osteodystrophy: role of calcimimetics.

In patients with secondary hyperparathyroidism (HPT), increased parathyroid hormone (PTH) secretion is triggered by low plasma calcitriol levels, hypocalcemia, and hyperphosphatemia. Vitamin D analogues have been used successfully to reduce PTH levels, but increases in serum calcium, phosphorus, and calcium x phosphorus ion product levels may occur. Second-generation calcimimetics have been shown to suppress PTH levels and also reduce calcium x phosphorus ion product. Potential indications are patients with secondary HPT, particularly those who respond to calcitriol therapy with an increase in calcium x phosphorus ion product. Coadministration of active vitamin D compounds may be necessary to overcome intestinal malabsorption of calcium and maintain normocalcemia in patients on long-term treatment with calcimimetics.