Premedication: Why is it Sometimes Necessary?
If your physician has ordered an imaging study that calls for a contrast media injection, they may also order a premedication that you need to take prior to your exam. Premedication is used to reduce the likelihood of a reaction to contrast. This treatment will be necessary if you have a prior history of a contrast allergy.
The prescription will require taking both prednisone (steroid) and BENADRYL® before the exam. According to the American College of Radiology Manual on Contrast Media, patients with a prior reaction to contrast media have a five times greater risk of experiencing another reaction.
In the past, it was thought that patients with seafood allergies were allergic to iodine. This has since been determined as false. There has been no evidence that a shellfish allergy is an indication that someone will also be allergic to contrast. Premedication isn’t necessary for those with shellfish allergies unless the reaction was severe.
Contrast will never be given to a patient with a history of a severe reaction to contrast media.
If you have been ordered a premedication prior to a study involving contrast, and you have additional questions, please talk to the physician who ordered your exam.