Recombinant PTH associated with hypercalcaemia and renal failure

Teriparatide (Forsteo) is a recombinant drug of the parathyroid hormone (PTH) family (it is the N-terminal sequence of 34 amino acids of the endogenous human PTH) that promotes bone formation through its direct effect on osteoblasts, indirectly increasing calcium resorption by the tubules as well as phosphate excretion by the kidneys. Its main indication is the treatment of osteoporosis [1, 2]. The use of teriparatide has been associated with, among other potential side-effects, the infrequent induction of mild hypercalcaemic episodes. However, the possibility of acute renal insufficiency or worsening of prior chronic kidney disease (CKD) has not been sufficiently emphasized. Here, we present the case of a 77-year-old male referred to our centre with acute impairment of renal function within the context of frequent use of nonsteroidal anti-inflammatory agents as well as drugs potentially causing hypercalcaemia, among which teriparatide was outstanding. This paper stresses some basic aspects of the diagnosis and current treatment of osteoporosis in patients with renal impairment and highlights the fact that teriparatide is contraindicated when CKD and secondary hyperparathyroidism are present.