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Pre-Medication Policy

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*Unless in the opinion of the responsible health care professional and supervising radiologist, the potential benefits outweigh the risks i.e. emergency situations.
In these instances, specific indications and reason(s) for exception should be documented in the report.


Premedication with steroids and Benadryl is now recommended only for patients who have had a reaction to contrast of a similar class (iodinated agents used during CT are one class, gadolinium based agents used during MRI are separate class) to the one planned to be given.

Prophylaxis for those with reactions to other allergens is no longer necessary.


This guideline has been drawn up based on the following information:

  • Current estimated overall reaction risk in the general population of children and adults is less than 1% (in range of 0.2-0.6%) (Wang et al., Dillman et al.)
  • Patients with a prior reaction to the same class of contrast agent being administered are known to be at highest risk for repeat reaction, 3 – 11% overall reaction rate with 2% break-through reaction rate even with pre-medication during CT (Mervak et al. Lasser et al).
  • The current standard of care in the United States is to pre-medicate patients with steroids and diphenhydramine to decrease risk of repeat contrast reaction in patients who have had a reaction in the past to a similar class contrast agent.
  • An IV steroid regimen (Recommended regimen below) is likely non-inferior compared to a longer PO regimen and is therefore recommended in the ED and in-patient setting to expedite imaging when needed (Mervak et al).
Allergic Like Reaction Definitions¹:


Mild
Moderate
Severe
Limited urticaria / pruritisDiffuse urticaria / pruritis
Diffuse edema, or facial edema with dyspnea
Nasal congestion
Diffuse erythema, stable vital signs
Diffuse erythema with hypotension
Cutaneous Edema
Facial edema without dyspneaLaryngeal edema with stridor and/or hypoxia
Sneezing / conjunctivitis / rhinorrhea
Throat tightness or hoarseness without dyspnea Wheezing / bronchospasm, significant hypoxia
Limited “itchy”/“scratchy” throat
Wheezing / bronchospasm, mild or no hypoxia
 Anaphylactic shock (hypotension + tachycardia)

¹ Physiologic reactions like nausea, vomiting, feeling of warmth are unlikely to benefit from pre-medication

References:

  • Wang CL, Cohan RH, Ellis JH, Caoili EM, Wang G, Francis IR. Frequency, outcome, and appropriateness of treatment of nonionic contrast media reactions. AJR 2008; 191:409–415.
  • Lasser EC, Berry CC, Mishkin MM, Williamson B, Zheutlin N, Silverman JM. Pretreatment with corticosteroids to prevent adverse reactions to nonionic contrast media. AJR 1994; 162:523–526.
  • Mervak BM, Davenport MS, Ellis JH, et al. Breakthrough reaction rates in high-risk inpatients premedicated before contrast-enhanced CT. AJR 2015; 205:77-84.
  • Dillman JR, Strouse PJ, Ellis JH, Cohan RH, Jan SC. Incidence and severity of acute allergic-like reactions to i.v. nonionic iodinated contrast material in children. AJR 2007; 188:1643-1647.
  • Mervak BM, Cohan RH, Ellis JH, Khalatbari S, Davenport MS. Intravenous Corticosteroid Premedication Administered 5 Hours before CT Compared with a Traditional 13-Hour Oral Regimen. Radiology 2017; 285:425-433.
  • American College of Radiology Contrast Manual. V103. 2018.

Pre-Medication Regimen

Premedication order set is now available in EPIC

Adult Out-patients:

  • 50mg prednisone PO 13, 7 and 1 hour before the injection.
  • 50mg diphenhydramine (Benadryl®) IV/PO within 1 hour of the injection.

Adult ED and In-Patients- alternative faster (but less proven) regimen is:

  • 200mg hydrocortisone IV 4 hours before injection.
  • 50mg diphenhydramine (Benadryl®) IV/PO within 1 hour of the injection.

Pediatric Out-patients (For patients less than 50kg):

  • Prednisone 0.7mg/kg (not to exceed 50mg) PO 13, 7 and 1 hour before the injection OR Prednisolone 0.7mg/kg (not to exceed 50mg) PO 13, 7 and 1 hour before the injection.
  • Diphenhydramine (Benadryl®) 1mg/kg IV/PO (not to exceed 50mg) within 1 hour of the injection.

Pediatric ED and In-Patients- alternative faster (but less proven) regimen is:

  • Hydrocortisone 1mg/kg (not to exceed 200mg) IV 4 hours before injection.
  • Diphenhydramine (Benadryl®) 1mg/kg IV/PO (not to exceed 50mg) within 1 hour
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