Masked Primary Hyperparathyroidism by Empagliflozin Use

Sodium-glucose cotransporter-2 inhibitors are drugs that regulate blood sugar by decreasing glucose reabsorption from the proximal renal tubules. Primary hyperparathyroidism masked by empagliflozin is very rare and only a few cases are reported in the literature. We report a case of a 57-year-old man with a known history of diabetes on empagliflozin for two years who presented with hypercalcemia and equivocal parathyroid hormone level. Upon cessation of this medication, he had persistent hypercalcemia with a raised parathyroid level, which confirmed the diagnosis of primary hyperparathyroidism. We believe this case is one of the first cases reported in the literature.