Effect of Cinacalcet on Renal Electrolyte Handling and Systemic Arterial Blood Pressure in Kidney Transplant Patients With Persistent Hyperparathyroidism

Background. The calcimimetic cinacalcet has recently been increasingly used for persistent hyperparathyroidism after renal transplantation. The present study investigated the short-term effects of cinacalcet on urinary electrolyte concentration and arterial blood pressure in kidney transplant patients with persistent hyperparathyroidism. Methods. In a prospective controlled single-center cross-over study, we examined 10 stable kidney transplant patients (mean estimated glomerular filtration rate 51 +/- 10 mL/min/1.73 m(2)) who received cinacalcet daily for persistent hyperparathyroidism. Urine specimens were collected at baseline and every 2 hr for a total study period of 6 hr after ingestion of 30 mg cinacalcet and without cinacalcet. Intact parathyroid hormone was determined at baseline and 2 hr later. Using ambulatory blood pressure measurement, arterial blood pressure was determined every 15 min. Results. Intact parathyroid hormone was significantly reduced with cinacalcet as compared with controls (-37 +/- 27.7% vs. -9.6 +/- 10.3%, P = 0.009). With cinacalcet, urinary calcium and magnesium concentration were increased (P = 0.042 and P = 0.007, respectively) and differed significantly as compared with the control phase without cinacalcet. After 4 hr, an increased urinary sodium concentration was also found compared with the control phase (P = 0.039). Systolic blood pressure was reduced with cinacalcet (P < 0.001) and differed significantly from control phase (-13.7 +/- 9.9 mm Hg vs. -3.2 +/- 5.2 mm Hg after 2 hr, P = 0.009; -18.1 +/- 10.8 mm Hg vs. -1.9 +/- 5.2 mm Hg after 4 hr, P = 0.001). Conclusions. In the short term, cinacalcet increases the urinary concentration of calcium, magnesium, and sodium. The observed antihypertensive effect might be beneficial in patients with a high cardiovascular risk after kidney transplantation.