NR3C2 and primary hyperparathyroidism: Nitta et al. did not observeany changes in serum levels of iPTH or the calcium x phosphorus product withspironolactone.14 Vukusich et al. alsodetected no changes in levels of calcium, phosphorus or iPTH resulting from the useof this drug.15 The EPATH study, whichexamined the effect of eplerenone, a selective MR antagonist on serum levels of iPTHin patients with primary hyperparathyroidism, found no changes in the levels of thishormone.23