Experience with metrizamide in patients with previous severe anaphylactoid reactions to ionic contrast agents.

Abstract

Metrizamide was employed in 6 patients who, during angiography, had severe anaphylactoid reactions to conventional ionic contrast media. Five patients received corticoid premedication before injection of conventional contrast medium and metrizamide; anaphylaxis occurred only after administration of conventional contrast media. Four patients had no detectable reaction after metrizamide; one had transient tachycardia. In the 6th patient, delayed edema developed in the region of his cerebral arteriovenous malformation. Observations suggested a marked decrease in the incidence and severity of anaphylactoid reactions when metrizamide was substituted in patients who had reacted to ionic contrast media. Metrizamide or a comparable nonionic contrast agent should be considered in patients who have had a severe reaction to conventional contrast medium.