Prophylaxis Policy for Patients Allergic to IV Contrast

  1. Ascertain the specific details of the prior reaction.  Determine:
    1. If the patient had a true reaction to intravascular contrast material
    2. Type of contrast used (if available)
    3. Type of reaction and severity – If the reaction was severe (laryngeal edema, anaphylaxis) the patient should not receive IV contrast again, even with premedication.  An exam without contrast or alternative test should be performed. If the reaction was mild or moderate (hives), premedication as below is appropriate.
    4. Treatment and its result
    5. Level of patient anxiety
  2. Determine if an examination without contrast or alternative test can provide adequate diagnostic information.
  3. If still convinced of the need for intravascular contrast, the service requesting  the scan should:
    1. Contact the radiologist scheduled on service for the proposed date of the study (GI/GU, CT, Angiography, Neuroradiology, or on-call resident for overnight/weekend Emergency Department patients).  If the staffing schedule is not available for the proposed date of the examination, then the Chief of the GI/GU Service (Dr. Perry Pickhardt), CT Service (Dr. Meghan Lubner), Angiography/Interventional Service (Dr. Orhan Ozkan), or Neuroradiology Service (consultant for the day) should be contacted.
    2. Discuss why an alternative imaging method will not suffice
    3. If the risk is determined to be acceptable; schedule the contrast examination and transmit prophylaxis instructions.
  4. Routine Contrast Reaction Prophylaxis (12 hour):
    1. Methylprednisolone (Medrol)
      1.  32 mg by mouth at 12 and 2 hours before contrast injection.
    2. Diphenhydramine (Benadryl):
      1. 50 mg intramuscular or oral 1 hour before contrast injection OR
      2. 50 mg (or 25 mg per height/weight indication) intravenously 15-20 min before contrast injection
        Note:  The Benadryl must be used with the proviso that the patient does not drive a car or operate heavy machinery 4-6 hours after the Benadryl is administered.
        NEJM 1987; 317: 845-849.
  5. Rapid Contrast Reaction Prophylaxis (5 hours):
    1. To be used only in a truly urgent situation after discussion between the requesting service and the appropriate radiology service.

    2. The requesting service must place a note in HealthLink outlining the necessity of contrast-enhanced examination and the rapid prohpylaxis protocol.

    3. Hydrocortisone:
      200 mg intravenously 5 and 1 hour before contrast injection
    4. Diphenhydramine (Benadryl):
      50 mg intravenously 1 hour before contrast injection

Greenberger PA et al. Emergency administration of radiocontrast media in high-risk patients. J Allergy CLin Immunol. 1986; 77(4): 630-634.

Mervak BM, Cohan RH, Ellis JH, Khalatbari S, Davenport MS.  Premedication administered 5 hours before CT compared with a Traditional 13-hour Oral regimen.  Radiology 2017; 285(2), 425-433.

 

 


7/2020