Comparison of patient responses to high- and low-osmolality contrast agents injected intravenously.

Low-osmolar intravascular radiographic contrast media have recently been introduced for clinical use in an attempt to reduce the frequency and severity of side effects. This study was undertaken to test patients' subjective reactions to IV injection of three different types of contrast media--iopamidol, meglumine/sodium ioxaglate, and sodium iothalamate. The low-osmolar contrast media (ioxaglate, iopamidol) were found to have a significantly lower frequency of nonidiosyncratic reactions than the high-osmolar contrast media (iothalamate). However, in view of the present cost of low-osmolar contrast media and the relatively minor nature of nonidiosyncratic reactions, it is concluded that high-osmolar contrast media should remain the contrast media of choice for routine IV use.