Systemic hypocalcemia after clinical injections of radiographic contrast media: amelioration by omission of calcium chelating agents.

Publisher Website
Google Scholar
Abstract
Intravascular injection of some radiographic contrast media causes a fall in the concentration of unbound serum Ca2+ and an increase in serum immunoreactive parathyroid hormone (iPTH). The decrease in Ca2+ levels was attributed to the presence in the contrast media of Ca2+ chelating agents (disodium edetate and sodium citrate) and to the effects of high ionic strength and hemodilution on Ca2+ activity. Omission of the Ca2+ chelating agents from solutions of diatrizoate may lessen the alterations in systemic Ca2+ metabolism. Renografin-76 (RG-76) (diatrizoate meglumine and diatrizoate sodium), which contains disodium edetate and sodium citrate was compared with Hypaque-76 (H-76) (diatrizoate meglumine, diatrizoate sodium), which contains no Ca2+ chelating activity. A bolus injection of a mean dose of 62 ml of either contrast medium decreased levels of Ca2+ significantly (P < 0.01) at 5 min. The decrease was significantly greater (P < 0.025) with RG-76 (0.096 .+-. 0.018 mM, mean) than it was with H-76 (0.049 .+-. 0.018 mM, mean). The level of iPTH increased (P < 0.01) by 68 .+-. 13 nl equivalents (nleq)/ml with RG-76 and by 28 .+-. 8 nleq/ml with H-76 (P < 0.01 vs. RG-76). In vitro, RG-76 decreased levels of Ca2+ in aqueous Ca2+ solutions 3.7-fold more than did H-76, but neither contrast medium had any direct effect on the PTH assay system. Omission of divalent cation chelating agents from solutions of diatrizoate reduces their effects on systemic Ca2+ metabolism.

This publication has 1 reference indexed in Scilit: