Studies on the acute toxicity of ionic and non-ionic contrast media following rapid intravenous injection. An experimental study in mice.

The influence of the injection rate on the acute intravenous toxicity (LD50) on mice of the ionic high osmotic contrast medium Isopaque Coronar (370 mg I/ml) and the non-ionic low osmotic Amipaque (370 mg I/ml) was investigated. At slow injection (0.1 ml/sec). Amipaque had a significantly higher LD50 than Isopaque Coronar (17.3 respectively 9.8 gm I/kg). Also at rapid injection (2 ml/10 sec). Amipaque was significantly less toxic than Isopaque Coronar (13.4 respectively 6.1 g I/kg). Thus Isopaque Coronar increased approximately 60% in toxicity while Amipaque increased 28% when the rate of injection was increased. This difference was statistically significant (p less than 0.001). Several possible mechanisms that might explain this difference, with special interest in the disturbances on the pulmonary circulation following contrast media injection, are discussed.