The administration of radiographic contrast media to patients with a history of a previous reaction.

Ninety-five patients were seen in consultation for previous reactions which their physicians considered as possible contraindications for the use of radiographic contrast media (RCM). Twenty-seven patients received no further studies because of a lack of sufficient indication to do them. The previous incidents in 26 were such that they were not classified as immediate generalized reactions (IGRs). Two of these patients had IGRs with repeat RCM (7.7%). Forty-two patients had previous reactions considered to be IGRs and medical problems such that repeat administration of RCM appeared essential for diagnosis. After pretreatment with diphenhydramine, 43 repeat procedures were performed in these patients followed by reactions, generally mild, in 7 (16%). Five of these were classified as IGRs (11.8%). The data on 264 similar patients in the literature were also reviewed. There appeared to be a higher incidence of IGRs to RCM in patients with a good history of a previous reaction than in the general population, but no severe reactions or fatalitics occurred in this entire series. The results showed that repeat studies in patients with previous reactions to RCM may be done, provided that there is careful evaluation of the initial reaction, the need for the diagnostic study, and provided appropriate precautions are taken prior to the procedure.