This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
[{'content': 'Drug of choice for acute attack of hereditary angioneurotic edema is \nSelect and explain. \nA. Danazol, B. Cl inhibitor concentrate, C. Icatibant, D. Methylprednisolone', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Icatibant (Firazyr), a selective bradykinin B2 receptor antagonist, was approved by the US Food and Drug Administration for treatment of acute attacks HAE in adults. Approval was based on 3 double-blind, randomized, controlled clinical trials known as For Angioedema Subcutaneous Treatment (FAST) Ref Davidson 23rd edition pg 481', 'role': 'assistant'}]