PTH and primary hyperparathyroidism: A simultaneous decrease of PTH and serum calcium levels due to the therapy apparently balances out this tendency towards hypercalciuria in many patients as, for example, one study found that cinacalcet safely normalized serum calcium and lowered PTH concentrations without increasing urinary calcium excretion in the study subjects, indicating the potential benefit of cinacalcet as a medical treatment for primary hyperparathyroidism [10].