This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuromuscular Blocker, Subject name: Anaesthesia
Cisatracurium, pure CIS isomer of atracurium all true except:- 
Select and explain. 
A. Is metabolized primarily by Hoffman degradation, B. Is cardiovascular stable, C. Produces more laudanosine than an equipotent dose of atracurium, D. Has onset & duration similar to atracurium
C: Produces more laudanosine than an equipotent dose of atracurium
Answer: C: Produces more laudanosine than an equipotent dose of atracurium 
Explanation: Atracurium molecule is mixture of 10 stereoisomers in which Cis isomer is only 15 %. A total Cis isomer was seperated and new drug was prepared which is Cisatracurium. Cisatracurium a pure CIS isomer of atracurium produces no /minimal histamine release and is more potent than atracurium. Thus it is given in less dose and causes less by product laudanosine production at equipotent dose.