Questionnaire survey of acute and delayed adverse reactions to ferumoxides

Purpose: The purpose of this study was to assess acute and delayed adverse reactions to ferumoxides. Materials and Methods: 473 consecutive patients who underwent ferumoxides-enhanced MRI were enrolled in this study. Following non-contrast-enhanced MRI, patients were interviewed about their allergic history, and after ferumoxides-enhanced MRI, they were asked to fill out a questionnaire sheet to record any symptoms within one week. Results: 345 of 473 questionnaires (72.9%) were returned. Fifty-eight of 345 patients (16.8%) showed some adverse reactions considered to be related to ferumoxides: 25 (7.2%) during administration, 25 (7.2%) later on the day of ferumoxides administration, and 17 (4.9%) within one week. Thirty-three patients (9.6%) showed only delayed adverse reactions. Delayed adverse reactions were more frequent in women than in men (p<0.01), and in patients with any allergic history than in those without such history (p<0.05). Acute adverse reactions tended to be more frequent in patients who had some adverse events to any contrast medium than in those with no such history (p=0.069). Conclusion: By using the questionnaire, the incidence of adverse reactions to ferumoxides (16.8%) was higher than previously reported from Japanese clinical trials.