Muscle relaxant of choice in renal and hepatic failure Is

Cis-Atracurium is an isomer of Atracurium. It undergoes inactivation in plasma by spontaneous non enzymatic degradation(Hoffman elimination) in addition to that by cholinesterases. Consequently it's duration of action is not altered in patients with hepatic or renal insufficiency.. All the other given drugs don't undergo Hoffman elimination. From KD Tripati 7th edition Page no 253