This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Aprepitant is used as: 
Select and explain. 
A. Anitidepressant, B. Antiemetic, C. Antihypeensive, D. Diuretic
B: Antiemetic
Answer: B: Antiemetic 
Explanation: The actions of substance P and neurokinins A and B are mediated by three G protein-coupled tachykinin receptors designated NK 1, NK 2, and NK 3. Several nonpeptide NK1 receptor antagonists have been developed. These compounds are highly selective and orally active, and enter the brain. Recent clinical trials have shown that these antagonists may be useful in treating depression and other disorders and in preventing chemotherapy-induced emesis. The first of these to be approved for the prevention of chemotherapy-induced nausea and vomiting is aprepitant. Ref: Katzung, 11th edition, Chapter 17.