INTRAVENOUS CALCITRIOL AS A TREATMENT OF SECONDARY REFRACTORY HYPERPARATHYROIDISM IN TERMINAL CHRONIC-RENAL-FAILURE

BACKGROUND: In advanced cases of secondary hyperparathyroidism (HPT) i n terminal chronic renal failure, the oral treatment of calcitriol is not possible due to the development of hypercalcemia. It has been demo nstrated that calcitriol directly inhibits the secretion of parathormo ne (PTH), independently of calcium. Therefore the intravenous administ ration of high and intermittent doses of calcitriol (ivVD) has been pr oposed as an alternative treatment for resistant HPT. METHODS: The res ponse of PTHi to treatment over 6 months with ivVD was evaluated in 18 patients with moderate-severe HPT resistent to the classical schedule s. RESULTS: An Important decrease was observed in the PTHi values (bas al: 698 +/- 277 pg/ml, end of treatment: 272 +/- 200; p < 0.05). Alkal ine phosphatase values followed a parallel course (basal: 476 +/- 286 U/l, end of treatment: 301 +/- 276 U/l, p < 0.05). Fifty-five percent of the patients presented hypercalcemia at some time (Ca greater-than- or-equal-to 11.5 mg/dl) being controlled by a decrease in the dosis of calcitriol or calcium in dialysis fluid. No response was observed in 3 patients (17 %) with treatment being discontinued due to presentatio n of uncontrollable CONCLUSIONS: The administration of intravenous cal citriol at high and intermittent doses is effective in a considerable number of patients with hyperparathyroidism resistent to the classical oral schedules. Its use may avoid surgical parathyroidectomy in some cases.