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': 'Drug with Ceiling effect: \nSelect and explain. \nA. Morphine, B. Buprenorphine, C. Fentanyl, D. Alfentanyl', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Buprenorphine Ceiling effect means paicular effect of drug increases with dose of drug, and when the ceiling (roof) is reached fuher incriment in dose not result in increase in effect. Opioid agonist - antagonist compounds produce respiratory depression (& anelgesia) with a ceiling effectQ. which means higher doses do not produce fuher respiratory depression and may actually result in increased ventilation (d/t predominance of antagonist actions)', 'role': 'assistant'}]