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': 'Which of the following anaesthetic drugs is contraindicated in chronic renal failure – \nSelect and explain. \nA. Morphine, B. Fentanyl, C. Pethidine, D. Atracurium', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Pethidine (Meperidine) is metabolized to form normeperidine (long half life) which is excreted by the kidney. Administration of pethidine to a patient with Chronic Renal Failure causes toxic accumulation of this metabo\xadlite and is hence contraindicated.', 'role': 'assistant'}]