Radiographic Contrast Media

1. See Also
   1. Intravenous Contrast Related Acute Renal Failure
2. Contraindications
   1. Pregnancy (risk of fetal Thyroid toxicity)
3. Contrast Agents
   1. High Osmolality (Higher risk of complications)
      1. Diatrizoate sodium (Hypaque)
      2. Iothalamate meglumine (Conray)
   2. Low Osmolality (Lower risk of complications)
      1. Ioxaglate meglumine (Hexabrix)
      2. Gadodiamide (Omniscan)
      3. Gadoteridol (ProHance)
      4. Iodixanol (Visipaque)
      5. Iopamidol (Isovue)
      6. Iopromide (Ultravist)
      7. Ioversol (Optiray)
4. Risk Factors for Contrast Reaction
   1. Older patient age
   2. Renal insufficiency
   3. History of contrast-related anaphylactoid reaction
   4. Asthma
   5. Allergic Rhinitis, medication or Food Allergy
   6. Comorbid conditions such as cardiovascular disease
   7. Concurrent Nephrotoxic Drugs such as NSAIDS
5. Adverse Effects
   1. Anaphylactoid Reaction
      1. Immediate reaction to small dose
      2. Emergency management (see Anaphylaxis)
         1. ABC Management
         2. Epinephrine 0.3 to 0.5 mg SQ q10-20 minutes
         3. Methylprednisolone 50 mg IV (for bronchospasm)
   2. Delayed reaction
      1. Constitutional symptoms occur >30 min post-contrast
      2. Management: Supportive
   3. Acute Tubular Necrosis (Acute Renal Failure)
      1. See Intravenous Contrast Related Acute Renal Failure
      2. Occurs more often if Acute Renal Failure Risk
   4. Local toxicity from extravasated Contrast Material
      1. Apply ice to area and elevate
      2. Reaction worse with ionic contrast agents
         1. High osmolality agents (Hypaque, Conray)
         2. Ioxaglate meglumine (Hexabrix)
6. Prevention
   1. See Intravenous Contrast Related Acute Renal Failure
   2. Use low osmolality agents if risk factors above
   3. Avoid concurrent use of Nephrotoxic Drugs
   4. Stop Glucophage (Metformin) 48 hours before contrast
      1. Risk of severe Lactic Acidosis
      2. Restart Glucophage when Renal Function normalized
   5. Consider N-Acetylcysteine before Intravenous Contrast
      1. See Intravenous Contrast Related Acute Renal Failure
   6. Hydrate before and after procedure
      1. Consider normal saline
      2. See Intravenous Contrast Related Acute Renal Failure
   7. Consider prevention of anaphylactoid reaction
      1. Indicated for prior radiocontrast reaction
      2. Corticosteroid protocol (either agent below)
         1. Methyl-Prednisolone 32 mg at 12 and 2 hours before
         2. Prednisone 50 mg at 13, 7 and 1 hour pre-contrast
      3. Antihistamines given also, 1 hour pre-contrast
         1. Diphenhydramine 50 mg at one hour pre-contrast and
         2. Cimetidine or Ranitidine 1 hour pre-contrast
7. References
   1. Maddox (2002) Am Fam Physician 66(7):1229-34
   2. Greenberger (1991) J Allergy Clin Immunol 87:867-72