Use of cinacalcet in nephrolithiasis associated with normocalcemic or hypercalcemic primary hyperparathyroidism: results of a prospective randomized pilot study

Objectives: To evaluate, by means of a prospective randomized study, the efficacy of cinacalcet in the forms of nephrolithiasis associated with primary hyperparathyroidism in both the hypercalcemic and normocalcemic variant. Materials and Methods: Ten patients suffering from active nephrolithiasis associated with primary hyperparathyroidism (4 hypercalcemics and 6 normocalcemics), equally divided between males and females, were randomly but not blindly addressed to treatment with potassium citrate and allopurinol, or to the same therapeutic regimen in combination with cinacalcet. The dosage of cinacalcet was optimized for each patient in order to obtain a reduction of parathyroid hormone (PTH) within normal limits while enabling the maintenance of adequate calcemic values. All study participants were given the same diet based on a reduction in sodium intake, oxalate-rich foods and animal protein with standardized intake of calcium and an increase in hydration. After a follow up period of 10 months , cinacalcet was associated to standard therapy and diet in patients who were not taken it, conversely cinacalcet was withdrawn in the remaining patients who remained on standard therapeutic regimen and diet. Follow up was continued for a second period of observation of the same duration of the first. Results: At the end of the period of treatment with cinacalcet, for both variants of hyperparathyroidism, a statistically significant reduction in the overall number and in the diameter of renal stones was found. Conclusions: This prospective randomized study shows the effectiveness of cinacalcet used in combination with a diet with normalized calcium intake, in reducing the number and size of urinary stones in hypercalemic and normocalcemic forms of primary hyperparathyroidism.