In an era of changing contrast agents, is there still a role for premedication in specific clinical scenarios to reduce recurrent hypersensitivity reactions after intravascular contrast agent administration?

Iodine-based contrast media (ICM) are an integral part of CT or angiography. Its use can lead to hypersensitivity reactions (HR), and the risk of recurrence is increased in patients with a prior HR or history of acute allergy. Premedication with corticosteroids and/or H1-antihistamines, dating from the era of ionic high-osmolar ICM, has been popular amongst radiologists. However, when used with nonionic low-osmolar ICM, the quality of evidence is low, efficacy in moderate-severe HR is suboptimal, frequent breakthrough reactions occur and can be severe, and its use can increase costs. There is a paucity of data for premedication use in high-risk patients in specific clinical scenarios, and, in general, accurate HR documentation and changing of the specific ICM, preferably with a different sidechain after allergologic evaluation, leads to better results. The imaging setting (hospital or clinic) and level of support in emergency situations will likely be important determinants of its use. There may be a niche indication for premedication in stressful emergency imaging of patients with a prior severe HR in which the culprit ICM is untraceable or unknown.