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Published on: July 21, 2011
Rates of idiosyncratic reactions. Ionic versus nonionic contrast media
1Department of Radiology, University of Texas Health Science Center at San Antonio 78284-7800.
Insights
Nonionic iodinated contrast agents are safer than ionic agents, with significantly lower rates of idiosyncratic reactions. This finding is supported by extensive research comparing different contrast media types.
Area of Science:
- Radiology
- Pharmacology
- Medical Imaging
Background:
- Idiosyncratic reactions to iodinated contrast agents have been studied for nearly 40 years.
- Conventional hyperosmolar agents have an estimated reaction rate of 5% and a repeat reaction rate exceeding 20%.
Purpose of the Study:
- To compare the rates of idiosyncratic reactions between ionic and nonionic iodinated contrast agents.
- To evaluate the safety profile of different types of iodinated contrast media.
Main Methods:
- A comprehensive literature review was performed.
- Included studies encompassed retrospective, prospective, and analytical multistudy reviews.
Main Results:
- Large comparative studies from the late 1980s showed significantly lower idiosyncratic reaction rates with nonionic agents compared to conventional ionic agents.
- Results regarding routine steroid administration before ionic agents were contradictory.
- Analytical reviews questioned the methodology of some studies but supported the enhanced safety of nonionic agents.
Conclusions:
- All iodinated contrast media possess excellent safety records.
- The majority of evidence indicates that nonionic contrast agents offer superior safety compared to ionic agents.
Rationale And Objectives:
Nearly 40 years ago, investigators began collecting data regarding idiosyncratic reactions to iodinated contrast agents. The rates of idiosyncratic reactions in patients receiving ionic contrast agents are compared with those found in patients receiving nonionic agents.
Methods:
A comprehensive literature review was conducted. Retrospective and prospective studies were included, as well as recent analytical multistudy reviews.
Results:
For conventional hypermolar agents, rates are estimated to be 5% and the rate of repeat reactions, greater than 20%. Large comparative studies conducted in the late 1980s found significantly lower rates of idiosyncratic reactions with the newer, nonionic agents than with conventional agents. The results of studies evaluating the use of routine administration of steroids before the use of ionic agents have been contradictory. Two analytical reviews of earlier research find fault with the methodology of most studies, but the reviewers supported the increased safety of nonionic agents.
Conclusions:
All iodinated contrast media have excellent safety records. Most evidence, however, demonstrates that nonionic agents are safer than ionic agents.
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