Perspectives on Adverse Reaction Rates Associated with the Use of High Osmolar Ionic and Low Osmolar Nonionic Contrast Media

Abstract

Downloaded from WILCOCK ET AL.media. This report presents the results of that review of the literature and of the evaluation of the data by Katayama et and concludes that the evidence indicates that differences exist in serious adverse drug reaction rates between ionic and nonionic CM. Content and organizationThis report first presents an overview of comparisons between ionic and nonionic CM in biological systems, including in vivo laboratory animal experiments and in vitro studies (Part I). Part I1 presents briefly the results of some recent studies comparing the effects of ionic and nonionic CM on components of the coagulation process in vitro. These findings are consistent with the concept that blood coagulation is inhibited to a greater degree by ionic iodinated CM. A description of adverse reactions to CM as reported in the smaller comparative studies involving direct comparisons of nonionic with ionic CM is included as Part 111 in order to show the concordance of findings between these studies and the Palmer'3' and Katayama et al.") studies.Part IV contains a critical evaluation of the two largest, most recent prospective studies comparing the incidence of adverse reactions associated with the use of the two kinds of contrast agents. This section includes a statement on the clinical perspective of the use of nonionic CM in radiographic procedures prepared by Harry W. Fischer, M.D. (former professor and chairman of the department of radiology, University of Rochester School of Medicine, Rochester, NY). An evaluation of the potential advantages of the use of nonionic CM over ionic CM with regard to the occurrence of severe adverse reactions can be found in Part V. Animal studies: General toxicityOverall, the acute toxicity, cardiovascular toxicity, and chemotoxicity data suggest that the nonionic CM are uniformly less toxic than the ionic CM. This finding is expected, since many of the observed toxic effects attributed to the use of CM are associated with the osmolarity of these agents relative to blood. Cardiovascular and hemodynamic aspects of CM are perhaps better studied than any other types of toxicity because of the extensive use of CM in cardiac angiography and the wealth of clinical data on cardiac function collected during such procedures, The use of nonionic CM appears to be associated with fewer cardiac-related adverse reactions than ionic CM, perhaps also due in large part to their lower osmolarity. Effect of contrast media on coagulationNonionic CM have relatively less anticoagulant activity than ionic CM. However, the clinical significance of this phenomenon is unknown. Current package inserts for both types of CM include statements about clotting potential based on in vitro studies. No new information was found that would alter the concept that ionic iodinated CM inhibit blood coagulation to a greater degree than nonionic CM.