Assuntos
Cálcio/uso terapêutico , Cardiopatias/tratamento farmacológico , Falência Renal Crônica/complicações , Doenças Vasculares/tratamento farmacológico , Vitamina D/uso terapêutico , Vitaminas/uso terapêutico , Adulto , Quimioterapia Combinada , Feminino , Cardiopatias/complicações , Humanos , Falência Renal Crônica/terapia , Masculino , Terapia de Substituição Renal , Resultado do Tratamento , Doenças Vasculares/complicaçõesAssuntos
Hiperparatireoidismo Secundário/tratamento farmacológico , Nefropatias/complicações , Naftalenos/uso terapêutico , Calcifediol/uso terapêutico , Doença Crônica , Cinacalcete , Relação Dose-Resposta a Droga , Humanos , Hiperparatireoidismo Secundário/sangue , Hiperparatireoidismo Secundário/etiologia , Hipocalcemia/induzido quimicamente , Hipocalcemia/tratamento farmacológico , Hormônio Paratireóideo/sangue , Fosfatos/metabolismo , Vitamina D/uso terapêutico , Deficiência de Vitamina D/prevenção & controleRESUMO
As suggested by its American brand name (Sensipar), the calcimimetic cinacalcet sensitizes the parathyroid cells to the extracellular calcium signal, suppressing parathyroid hormone (PTH) release and synthesis and preventing parathyroid cell proliferation. This primary PTH suppression decreases the release of calcium and phosphate from bone without increasing intestinal absorption of calcium and phosphate. Therefore cinacalcet decreases the risk of hypercalcemia and hyperphosphatemia in contrast to 1alpha-OH vitamin D derivatives. Compared with calcium-containing oral phosphate binder (OPB), it increases the risk of hypocalcemia and may decrease the PTH-mediated phosphaturia in predialysis patients. This justifies its combined use with calcium-containing OPB in order to prevent hypocalcemia and enhance the hypophosphatemic effect of the latter, while improving PTH suppression. The National Kidney Foundation (NKF) Kidney Disease Outcomes Quality Initiative (K/DOQI) has recommended restriction of supplemental elemental calcium to 1.5 g/day, a recommendation that we believe should be revised. No pathophysiologic or randomized trial data have yet evidenced the absolute necessity for systematically using 1alpha-OH vitamin D derivatives and noncalcium-containing OPB rather than higher doses of calcium-containing OPB alone in uremic patients without vitamin D insufficiency. In patients with hyperparathyroidism as severe as in the "Treat to Goal Study," the Durham study showed that a calcium carbonate dose more than three times the K/DOQI limit could decrease PTH into the recommended range, with the advantage of a lower calcium-phosphate product compared with the combination of calcitriol and noncalcium OPB. Besides the efficient PTH suppression associated with lower calcium-phosphate product and a good gastrointestinal tolerance, long-term data suggest that cinacalcet may decrease the risk of parathyroidectomy and fracture, while high bone turnover lesions are improved. However, no long-term data on bone mineral density and cardiovascular calcification and complications are yet available. Such studies, along with those comparing cinacalcet and 1alpha-OH vitamin D-based approaches to hyperparathyroidism, are needed.