Successful Graded Dose Challenge to Iodixanol Radiocontrast Media in a Patient With Delayed Anaphylaxis to Iohexol

We present a case of an 82-year-old male with known radiocontrast media (RCM) hypersensitivity who was admitted to our hospital with gangrene of his right toe. The plan for revascularization of his lower extremity required an angiogram. This presented a management challenge as the patient had experienced 2 episodes of delayed anaphylaxis to Omnipaque (iohexol) RCM, and based on a literature review, there was no known or established precedent on a safe procedure in these situations. The patient was premedicated and given a graded dose challenge of an alternative RCM (iodixanol) prior to the radiographic study. He was given 1% of the total expected dose 1 hour before to the procedure and an additional 10% for the 30 minutes prior. He was then given the final dose in the operating room. Following angiogram, the patient was monitored for 18 hours in the postanesthesia care unit, with no adverse reactions. He was placed on a prednisone taper for 1 week, with daily diphenhydramine. The patient remained asymptomatic throughout the hospital course. This novel approach to RCM hypersensitivity management lends itself to a hope that graded dose challenges may play a greater role in the management of these patients.