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
[{'content': 'Narcotic of choice for out patient anesthesia: \nSelect and explain. \nA. Morphine, B. Alfentanyl, C. Fentanyl, D. Pethidine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Alfentanyl All of these are sho acting narcotic analgesics the shoest acting among them is Remifentanil. Drug Onset Duration of action Remifentanil 30 - 60 second 3 - 5 minute Alfentanil 0.5 minute 5 - 10 minute Fentanyl & Sufentanil 1 - 4 minute 30 minute . - Remifentanyl, Alfentanyl & Sufentanil have sho duration of action so can be used as outpatient anesthetic agents. Desflurane & Sevoflurane provide the fastest wake up time among volatile anesthetic outpatient agents.', 'role': 'assistant'}]