: Firstly, consider alternative non-contrast imaging strategies (e.g. non-contrast MRI or CT, ultrasound or nuclear medicine.) for moderate and severe reaction

Pre-medication is usually not necessary.

Pre-medication is recommended.

• If a study with contrast is eventually deemed to be necessary, then after consultation with clinical team, written informed consent of the patient or representative must be obtained by the radiologist or their physician delegate and anesthesia notified.
• Premedication with corticosteroids is necessary.
• Examination should be done in a hospital setting.

Pre-medication is recommended.

Premedication may be indicated.

If a patient has had a prior reaction to iodinated intravenous contrast and has inflammatory bowel disease, bowel ischemia, or bowel obstruction, iodinated oral contrast agents should not be used.

If it is necessary for the patient to be treated before having a contrast-enhanced exam:

1. Radiologist or their physician delegate to obtain written informed consent for contrast-enhanced exam, and
2. Pre-medicate the patient with corticosteroids (see below), and
3. Do the contrast-enhanced study in a hospital setting.

• Methylprednisolone (Medrol®) 32 mg by mouth at 12 hours and 2 hours before contrast medium injection OR prednisone, 50 mg by mouth at 13, 7, and 1 hours before the contrast medium injection
• Optional addition: Diphenhydramine (Benadryl®) 25 mg by mouth, one hour before the contrast medium injection can be added to the corticosteroids prep (patient should not drive to appointment.)
• Use a nonionic, low-osmolality contrast medium.
• In emergency situations, three dose intravenous corticosteroid (e.g., 200 mg hydrocortisone) begun 6 hours before the study and repeated at 4-6 hours, plus 50 mg diphenhydramine 1 hour before the procedure, has been used.

By W Shuman, M Gunn, W Bush, C Wang, Y Anzai February 9, 2010