A prospective, parallel, double-blind comparison of iodixanol and iohexol in extremity phlebography

A two-center, prospective, double-blind study was conducted to compare the performance parameters (efficacy, safety, and injection-associated discomfort) of iohexol with those of the new, isosmolar contrast medium iodixanol in extremity phlebography.

Ninety-nine patients from two centers, for whom venography was clinically indicated, were blindly randomized into two groups, iohexol at 300 mg I/ml (IOH 300) or iodixanol at 270 mg I/ml (IOD-270). Patient vital signs and reports of adverse events were recorded for a minimum of 1 hr and monitored until the outcome was known. Any discomfort associated with the injection was also recorded. Laboratory measures included urinalysis, creatinine levels in serum and blood urea nitrogen.

Both contrast media provided good or excellent visualization in nearly all patients (100% of patients in the IOD-270 group and 96% in the IOH-300 group). The incidence of adverse reactions was low in both groups (8.5% in the IOD-270 group and 10% in the IOH-300 group). Injection associated discomfort lasting less than 4 min occurred in nine patients, four in the IOD-270 group and five in the IOH-300 group. Although clinically relevant changes in vital signs occurred in more than half the patients, most were judged to be anxiety related. Review of laboratory data revealed no evidence of toxicity for either agent. There was no statistically significant difference between the two agents with regard to any of these observed parameters.

The data support the conclusion that both IOD-270 and IOH-300 are safe and effective agents when used for adult phlebography and are associated with little injection-site discomfort.