Are there any differences in acute adverse reactions among five low-osmolar non-ionic iodinated contrast media?

The differences regarding adverse reactions in different low-osmolar non-ionic contrast media had not been investigated previously. Thus, the aims of this study were to identify differences in the incidence of adverse reactions in five different low-osmolar non-ionic contrast media. We prospectively recorded all adverse events associated with five different low-osmolar non-ionic contrast media used in 8,931 consecutive patients for CT. Patients were randomly assigned to five groups: iomeprol 300 mgI/ml, iopamidol 300 mgI/ml, iohexol 300 mgI/ml, iopromide 300 mgI/ml and ioversol 320 mgI/ml. Adverse events were observed in 241 patients (2.7%). The incidence of acute adverse reactions was significantly higher in the following groups: (1) iomeprol (3.9%) and iopromide (3.5%) groups, (2) patients aged 59 years or less (4.5%) compared with those aged 60 years or over (1.9%), (3) the first period (3.5%) compared with the late period (2.3%), (4) those with a past history of adverse reactions to contrast media (11.2%), and (5) patients receiving contrast media for the first time (3.3%) compared with those had received it previously (2.0%). The incidence of acute adverse reactions may be reduced in younger patients by using iopamidol, iohexol and ioversol.