Imaging Pearls ❯ Contrast ❯ Premedication for Contrast Reactions
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- Key outcomes from a multidisciplinary task force on hypersensitivity reactions to iodinated contrast media include recommendations to document reactions thoroughly in the electronic health record, including symptoms and the specific inciting agent, and a discussion of varying strategies for avoidance of repeat acute hypersensitivity reactions to iodinated contrast media according to the severity of the index reaction; importantly, no corticosteroid premedication is generally recommended for patients with a prior mild acute hypersensitivity reaction.
Management and Prevention of Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement From the American College of Radiology and the AAAAI.
Wang C, Ramsey A, Lang D, et al.
J Allergy Clin Immunol Pract. 2025 Mar 10:S2213-2198(25)00191-6. doi: 10.1016/j.jaip.2025.01.042. Epub ahead of print. - For patients with a history of mild immediate ICM hypersensitivity reactions, premedication is not recommended; this is a change from prior American College of Radiology recommendations. Switching the contrast agent is recommended when the inciting agent(s) is known and when feasible.
Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement From the American College of Radiology and the AAAAI.
Wang C, Ramsey A, Lang D, et al.
J Allergy Clin Immunol Pract. 2025 Mar 10:S2213-2198(25)00191-6. doi: 10.1016/j.jaip.2025.01.042. Epub ahead of print. - For patients with a history of severe immediate ICM hypersensitivity reactions, it is recommended first to consider alternative imaging studies. If there is no acceptable alternative study that does not entail exposure to the same class of contrast, premedication is recommended and switching the contrast agent is recommended when feasible; this is a change from the most recent Joint Task Force Practice Parameters on Anaphylaxis. The study should be performed in a hospital setting with a rapid response team available, including personnel, equipment, and supplies to treat anaphylaxis.
Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement From the American College of Radiology and the AAAAI.
Wang C, Ramsey A, Lang D, et al.
J Allergy Clin Immunol Pract. 2025 Mar 10:S2213-2198(25)00191-6. doi: 10.1016/j.jaip.2025.01.042. Epub ahead of print. - No premedication is necessary for patients with prior chemotoxic or physiologic reactions or an isolated history of shellfish allergy or iodine allergy including topical povidone-iodine.
Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement From the American College of Radiology and the AAAAI.
Wang C, Ramsey A, Lang D, et al.
J Allergy Clin Immunol Pract. 2025 Mar 10:S2213-2198(25)00191-6. doi: 10.1016/j.jaip.2025.01.042. Epub ahead of print. - ”The risk of adverse immediate ICM reactions has been dramatically reduced with the universal use of LOCM. There is no high-quality evidence supporting the benefit of corticosteroid premedication in preventing recurrent reactions in patients receiving LOCM, owing to variations in premedication protocols and the low rate of severe reactions to LOCM. Despite these unproven and modest benefits, a survey of radiologists in 2009 showed increasing support for using premedication regimens compared with 1995.”
Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement From the American College of Radiology and the AAAAI.
Wang C, Ramsey A, Lang D, et al.
J Allergy Clin Immunol Pract. 2025 Mar 10:S2213-2198(25)00191-6. doi: 10.1016/j.jaip.2025.01.042. Epub ahead of print. - “This document contains joint consensus statements endorsed by the ACR and the AAAAI, which are intended to improve and standardize the care of patients who experience or have a history of an adverse reaction to ICM. These consensus recommendations are based on the best evidence and apply only to intravenous administration of ICM. High-quality evidence and methodologically rigorous studies are lacking owing to (1) the rarity of moderate and severe reactions to low-osmolality iodinated contrast agents; (2) the paucity of methodologically sound studies; and (3) the heterogeneity of published studies, including the multiplicity of premedication and ST regimens, variations in patient selection for premedication, and differing contrast agents used in switching methodology. These recommendations should not be taken as definitive standards of practice; they may be subject to change once additional and more definitive evidence becomes available.”
Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement From the American College of Radiology and the AAAAI.
Wang C, Ramsey A, Lang D, et al.
J Allergy Clin Immunol Pract. 2025 Mar 10:S2213-2198(25)00191-6. doi: 10.1016/j.jaip.2025.01.042. Epub ahead of print. - - Documentation of iodinated contrast media (ICM) hypersensitivity reactions, including symptoms and the specific inciting agent in the electronic medical record, is recommended to optimize future ICM reaction management.
- High-quality evidence and methodologically rigorous studies are lacking owing to: (a) the rarity of moderate and severe reactions to low-osmolality iodinated contrast agents; (b) the paucity of methodologically sound studies; and (c) the heterogeneity of published studies, including the multiplicity of premedication and skin testing regimens, variations in patient selection for premedication, and differing contrast agents used in switching methodology.
Management and Prevention of Hypersensitivity Reactions to Radiocontrast Media: A Consensus Statement From the American College of Radiology and the AAAAI.
Wang C, Ramsey A, Lang D, et al.
J Allergy Clin Immunol Pract. 2025 Mar 10:S2213-2198(25)00191-6. doi: 10.1016/j.jaip.2025.01.042. Epub ahead of print.
- Patients premedicated for a prior contrast reaction have a breakthrough reaction rate (2.1%) that is 3-4 times the ordinary reaction rate in the general population, while patients premedicated for other indications have a breakthrough reaction rate close to 0% [29]. In most cases (~81%), breakthrough reaction severity is similar to index reaction severity.
ACR Manual On Contrast Media 2023 - 12- or 13-hour oral premedication maybe considered in the following settings:
1. Outpatient with a prior allergic-like or unknown-type contrast reaction to the same class of contrast medium (e.g., iodinated – iodinated).
2. Emergency department patient or inpatient with a prior allergic-like or unknown-type contrast reaction to the same class of contrast medium (e.g., iodinated – iodinated) in whom the use of premedication is not anticipated to adversely delay care decisions or treatment.
ACR Manual On Contrast Media 2023 - Accelerated IV premedication may be considered in the following settings:
1. Outpatient with a prior allergic-like or unknown-type contrast reaction to the same class of contrast medium (e.g., iodinated – iodinated) who has arrived for a contrast-enhanced examination but has not been premedicated and whose examination cannot be easily rescheduled.
2. Emergency department patient or inpatient with a prior allergic-like or unknown-type contrast reaction to the same class of contrast medium (e.g., iodinated – iodinated) in whom the use of 12- or 13-hour premedication is anticipated to adversely delay care decisions or treatment.
ACR Manual On Contrast Media 2023 - Accelerated IV premedication may be considered in the following settings:
1. Outpatient with a prior allergic-like or unknown-type contrast reaction to the same class of contrast medium (e.g., iodinated – iodinated) who has arrived for a contrast-enhanced examination but has not been premedicated and whose examination cannot be easily rescheduled.
2. Emergency department patient or inpatient with a prior allergic-like or unknown-type contrast reaction to the same class of contrast medium (e.g., iodinated – iodinated) in whom the use of 12- or 13-hour premedication is anticipated to adversely delay care decisions or treatment.
ACR Manual On Contrast Media 2023 - In rare clinical situations, the urgency of a contrast-enhanced examination may outweigh the benefits of prophylaxis, regardless of duration, necessitating that contrast medium be administered to a high-risk patient in the absence of premedication. This determination is best made jointly by the radiology team, the referring service, and potentially the patient (if feasible). In such cases, a team of individuals skilled in resuscitation should be available during the injection to monitor for and appropriately manage any developing reaction.
ACR Manual On Contrast Media 2023 - Elective Premedication (12- or 13-hour oral premedication)
1. Prednisone-based: 50 mg prednisone by mouth at 13 hours, 7 hours, and 1 hour before contrast medium administration, plus 50 mg diphenhydramine intravenously, intramuscularly, or by mouth 1 hour before contrast medium administration [22]. Or
2. Methylprednisolone-based: 32 mg methylprednisolone by mouth 12 hours and 2 hours before contrast medium administration. 50 mg diphenhydramine may be added as in option 1 [39].
Although never formally compared, both regimens are considered similarly effective. The presence of diphenhydramine in regimen 1 and not in regimen 2 is historical and not evidence-based. Therefore, diphenhydramine may be considered optional.
ACR Manual On Contrast Media 2023