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
[{'content': 'Which of the following drugs is contraindicated in acute intermittent porphyria? \nSelect and explain. \nA. Thiopentone, B. Midazolam, C. Propofol, D. Etomidate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Barbiturates are contra-indicated in acute intermittent porphyria.', 'role': 'assistant'}]