Are there specific patients or risk factors that make it more likely to get a contrast reaction?

Predisposing risk factors for general acute adverse reactions to contrast media are: Note: increased predisposing risk factors does not mean the patient can not get IV contrast. It simply means that potentially they are at higher risk compared to other patients. Previous adverse reactions History of asthma History of allergy Heart disease Dehydration Hematological conditions like sickle cell anemia, polycythemia and myeloma Pre-existing renal disease Infants and the elderly Anxiety Beta blockers, NSAIDs, interleukin 2 Adverse reactions to Intravenous Iodinated Contrast Media: A Primer for Radiologists  Namasivayam S et al.  Emerg Radiol (2006)12; 210-215