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: Anaesthesia
The following are used for treatment of postoperative nausea and vomiting following squint surgery in children except: 
Select and explain. 
A. Ketamine, B. Ondansetron, C. Propofol, D. Dexamethasone
A: Ketamine
Answer: A: Ketamine 
Explanation: Ketamine is not used for treatment of postoperative nausea and vomiting. In fact ketamine use is itself associated with nausea and vomiting and requires prophylaxis. Ref: Lee's Synopsis of Anaesthesia, 12th Edition, Page 192; Textbook of Anaesthesia By Aitkinhead, 4th Edition, Pages 176, 244-49