Histamine release and pseudoallergic reactions induced by radiographic contrast media: comparison of Angiographin, Hexabrix and Telebrix using an in vivo canine model.

Radiographic contrast media (RCM) in clinical use cause unwanted allergic/pseudoallergic reactions of all grades of severity. They also induce histamine release from a variety of mast cell populations, the extent of the histamine release reaction depending on both the organ and species. In this study 3 RCM, which had been previously shown to be effective histamine releasing agents with canine liver cells, were investigated using an in vivo canine model based on the clinical situation. The dogs (n = 36) were randomly allocated to one of 3 treatment groups and received a bolus injection (2 ml/kg body weight) of either Angiographin, Hexabrix or Telebrix. Blood pressure was monitored continuously and blood sampling, for plasma histamine measurements, was performed before and 1, 5, 10, 20 and 30 min after RCM injection. All 3 RCM caused elevated plasma histamine levels in some animals: Angiographin 9 of 12 dogs, 0.40 ng/ml, (0-1.9 ng/ml) median (range); Hexabrix 11/12, 0.5 ng/ml (0-3.8 ng/ml); Telebrix 7/12, 0.4 ng/ml (0-2.0 ng/ml). Cardiovascular reactions were observed in most animals. The hypotensive reactions occurred with a maximum 30 sec after RCM application and recovery was normally observed after 1-1.5 min. The response after Angiographin or Telebrix was significantly greater than after Hexabrix. Hypertensive reactions occurred later (15 min (5-25 min)) and did not differ between the groups. All 3 agents tested were able to elicit histamine release and cardiovascular reactions. In comparison to histamine release occurring after intravenous administration of other agents, such as hypnotics, the degree of histamine release was small.(ABSTRACT TRUNCATED AT 250 WORDS)