Who is at risk for a reaction?
Those at higher risk involve patients with a previous history of contrast allergy, severe asthma and, possibly, allergy to shellfish (controversial). Contrast reactions are unpredictable and it cannot be stated with certainty as to whether a patient will have a reaction or not. Diabetic patients taking Metformin should inform the staff of this as contrast can temporarily worsen kidney function in such patients. There are some steps that can be taken to minimize this side effect. Overall, contrast is safe in the vast majority of patients. By comparison 1 in 1,000 people have a serious allergy to aspirin or penicillin.
