Reason for preferring cis-Atracurium over Atracurium is

* Cis-Atracurium is a R enantiomer of Atracurium that does not provoke histamine release. Compared to Atracurium, Cis-Atracurium is: - * 4 times more potent * Slow in onset of action, but similar duration of action * Not hydrolysed by plasma cholinesterase and has limited hepatic metabolism --> less amount of toxic metabolites are formed. (Cis-Atra also undergoes Hoffman elimination) * Does not provoke histamine release, lesser side effects * Cis-Atracurium is preferred skeletal muscle relaxant in elderly patients and for patients with liver/kidney disease. Ref:- Goodman & Gilman Pharmacological Basis of Therapeutics 13th Ed; Pg num:- 188