title: Delayed vs. immediate adverse reactions to ionic and non-ionic low-osmolality contrast media.
abstract: OBJECTIVE
  To evaluate the correlation between immediate and delayed adverse reactions to low-osmolality ionic and non-ionic contrast media.
  
  
  METHODS
  A comparative survey of 984 consecutive patients was performed using contrast enhanced CT examination; 472 patients were administered ioxaglate, 512 iopamidol. The immediate adverse reactions were recorded during and after completion of the injection, and delayed reactions were surveyed by questionnaire. Delayed reactions were analyzed in 242 patients of the ioxaglate group and 215 of the iopamidol group from whom questionnaires were returned. The incidence of delayed adverse reactions was evaluated in comparison with immediate reactions.
  
  
  RESULTS
  The incidence of immediate reactions in the iopamidol group (6.4%) was lower than that in the ioxaglate group (23.9%) (p < 0.01). There was no statistically significant difference in delayed reactions between the two groups: 16.5% for ioxaglate vs. 14.9% for iopamidol. History of allergy was relatively highly correlated with the incidence of delayed reactions in the ioxaglate group, but not in the iopamidol group. Thirty-two of 40 ioxaglate cases and all of the iopamidol group who reported delayed reactions were without immediate reactions.
  
  
  CONCLUSIONS
  It is not possible to predict delayed reaction on the basis of a history of allergy or manifestation of a preexisting immediate reaction.
authors.affiliation: Department of Radiology, Osaka Teishin Hospital, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Oi
authors.forename: H
authors.initials: H
authors.lastname: Yamazaki
authors.forename: M
authors.initials: M
authors.lastname: Matsushita
mesh_terms: D003287:Contrast Media / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000009:adverse effects*; D007485:Ioxaglic Acid / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007479:Iopamidol; D007485:Ioxaglic Acid