Incidence of Amiodarone Hypersensitivity in Patients with Previous Allergy to Iodine or Iodinated Contrast Agents

Study Objective To determine the incidence and nature of allergic reactions to amiodarone in hospitalized patients with a listed allergy to iodine or iodinated radiocontrast agents. Design Retrospective medical record review. Setting Two academic medical centers. Patients A total of 234 sequential hospitalized patients with a listed iodine and/or iodinated radiocontrast agent allergy who received oral or intravenous amiodarone between January 2006 and December 2010. Measurements and Main Results Demographic and clinical data, as well as documentation of an allergic reaction to amiodarone, were collected for each patient from electronic medical records. Mean +/- SD age was 69 +/- 12years, and 51% were male. Of the 234 patients, 167 (71%) had a listed previous allergy to iodinated contrast agents, 55 (24%) to iodine, and 12 (5%) to both. Patients received an average inpatient total dose of 2.9 +/- 3.2 g of either oral (106 patients [45%]), intravenous (39 patients [17%]), or both oral and intravenous (89 patients [38%]) amiodarone. Only 1 (0.4%) of the 234 patients was identified as having a probable allergic reaction to amiodarone (score of 6 on the Naranjo adverse drug reaction probability scale). One additional patient receiving intravenous amiodarone experienced a rash that was determined to be caused by an antibiotic. All other patients received amiodarone without any identifiable allergic reactions. Conclusion The incidence of hypersensitivity reaction to amiodarone in hospitalized patients with a listed allergy to iodine or iodinated contrast agents was less than 1%, and all identified reactions were without long-term sequelae. Allergy to iodine and iodinated contrast agents may not be a valid absolute contraindication to amiodarone administration in the inpatient setting.