Can angiography be done for contrast allergy? Some patients who are allergic to contrast agents but have obvious angina pectoris or myocardial infarction and need angiography urgently in clinical practice can undergo coronary angiography with H1 blocker paracetamol, H2 blocker famotidine, and dexamethasone triplet intravenous anti-allergy prophylaxis before angiography.