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
Drug of choice for acute attack of hereditary angioneurotic edema is 
Select and explain. 
A. Danazol, B. Cl inhibitor concentrate, C. Icatibant, D. Methylprednisolone
C: Icatibant
Answer: C: Icatibant 
Explanation: 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