[Intravenous calcitriol in the treatment of the refractory secondary hyperparathyroidism of terminal chronic kidney failure].

BACKGROUND

In advanced cases of secondary hyperparathyroidism (HPT) in terminal chronic renal failure, the oral treatment of calcitriol is not possible due to the development of hypercalcemia. It has been demonstrated that calcitriol directly inhibits the secretion of parathormone (PTH), independently of calcium. Therefore the intravenous administration of high and intermittent doses of calcitriol (ivVD) has been proposed as an alternative treatment for resistant HPT.

METHODS

The response of PTHi to treatment over 6 months with ivVD was evaluated in 18 patients with moderate-severe HPT resistant to the classical schedules.

RESULTS

An important decrease was observed in the PTHi values (basal: 698 +/- 277 pg/ml, end of treatment: 272 +/- 200; p < 0.05). Alkaline 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 > or = 11.5 mg/dl) being controlled by a decrease in the doses of calcitriol or calcium in dialysis fluid. No response was observed in 3 patients (17%) with treatment being discontinued due to presentation of uncontrollable hypercalcemia.

CONCLUSIONS

The administration of intravenous calcitriol at high and intermittent doses is effective in a considerable number of patients with hyperparathyroidism resistant to the classical oral schedules. Its use may avoid surgical parathyroidectomy in some cases.