Iothalamate Meglumine/Iothalamate Sodium

The radiopacity and complications of meglumine iothalamate 52% and sodium iothalamate 26% (Vascoray®) were compared with those of meglumine diatrizoate 66% and sodium diatrizoate 10% (Renografin®‐76) in 2258 patients with and without cardiac disease. There was no difference in radiopacity and the type and incidence of adverse reactions were similar, but the frequency was significantly higher (p < 0.05) with Vascoray® in patients with constrictive pericarditis, dissecting aortic aneurysm, and primary pulmonary hypertension. The difference in the frequency of hypotension, sinus bradycardia, and transient asystole in the Renografin®‐76 and Vascoray® groups was statistically significant. Ventricular arrhythmias occurred in 6% of the patients with primary myocardial disease compared to an average of 0.7% in those without this cardiac abnormality (p < 0.01), but there was no significant difference in the frequency in the two contrast agent groups. All reactions were treated and the studies were performed without mortality. Results of this study show that iothalamate formulation with sodium to meglumine ratio of 1:2 containing 410 mEq/L of sodium (Vascoray®) is suitable and safe for clinical use for roentgenographic studies of the heart, and coronary artery circulation.

Several contrast media were tested for their ability to release serotonin from whole blood. Renografin-60, Hypaque M-75, Vascoray and Conray were incubated with human blood at 37 degrees C for 60 min. Platelet-poor plasma was analysed for serotonin using a high performance liquid chromatographic technique. Seven non-ionic contrast media were similarly incubated and serotonin levels determined. Ionic contrast media induced a greater release of serotonin compared with non-ionic ones. The amount of serotonin was not proportional to iodine concentration in blood. These results suggest that hypertonic solutions of contrast media produce a physical injury to platelets causing them to release their granular contents.