Adverse reactions following two separate intravascular injections of contrast media in the same patient. A comparison between iohexol and monomeric ionic media.

Adverse reactions following contrast medium injections in 26 non-comparative and parallel trials were extracted from the iohexol vascular clinical trial program in Northern Europe. Six hundred and forty-one patients (13-88 years old) in whom information was available about a vascular contrast medium examination before the iohexol clinical trials were included, enabling a retrospective within patient comparison of adverse reactions. Iohexol gave a lower recurrence frequency (approximately 3.5 times) of reactions than ionic monomers in patients who previously experienced adverse reactions to vascular contrast media. In order to overcome some of the drawbacks with the present retrospective design, prospective comparative studies are recommended.