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
Laudanosine is a metabolite of: 
Select and explain. 
A. Atracurium, B. Cis-atracurium, C. Pancuronium, D. Vecuronium
A: Atracurium
Answer: A: Atracurium 
Explanation: 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.