[Activation of the kallikrein-kinin system by intravenous administration of ionic and non-ionic radiographic contrast media].

Conventional ionic contrast media (sodium meglumine and amidotrizoate) were injected intravenously in 22 patients (group A); the nonionic, low-osmolar contrast medium iohexol was similarly administered to 24 patients (group B). This resulted in a significant (group A: P less than 0.05; group B: P less than 0.01) reduction in prekallikrein (93 and 94%, respectively), inhibition of kallikrein (90 and 88%), beta-factor XIIa inhibition (86 and 85%), and C1 inhibition (90 and 91%). Factor XII levels remained unchanged in both groups. These results indicate that the kallikrein-kinin system is activated even during routine, complication-free radiographic procedures involving contrast-media injection. There was no difference between ionic and nonionic contrast media.