This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anaesthesia, Subject name: Pharmacology
[{'content': 'Laudanosine is a metabolite of: \nSelect and explain. \nA. Atracurium, B. Cis-atracurium, C. Pancuronium, D. Vecuronium', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. (A) Atracurium(Ref: Miller 7th/e p880)Both atracurium and cis-atracurium are eliminated by Hoffman's elimination. Atracurium is also metabolized by liver to some extent and result in production of a metabolite, laudanosine that can cause CNS toxicity including seizures. On the other hand cis-atracurium is almost completely eliminated by Hoffman's elimination and produce negligible laudanosine.", 'role': 'assistant'}]