The orally bioavailable hydrochloride salt of the calcimimetic cinacalcet. Cinacalcet increases the sensitivity of calcium-sensing receptors on chief cells in the parathyroid gland to extracellular calcium, thereby reducing parathyroid hormone (PTH) secretion. A reduction in PTH levels inhibits osteoclast activity, which may result in a decrease in cortical bone turnover and bone fibrosis, and normalization of serum calcium and phosphorus levels. In addition, by reducing PTH levels, cinacalcet may reduce PSA levels; PTH appears to raise PSA levels and may increase prostate cancer cell growth.