<prompt> Muscle relaxant of choice in renal and hepatic failure IsCis-atracuriumVecuroniumRocuroniumRapacuronium  <response>: Cis-Atracurium is an isomer of Atracurium. It undergoes inactivation in plasma by spontaneous non enzymatic degradationHoffman elimination in addition to that by cholinesterases. Consequently its duration of action is not altered in patients with hepatic or renal insufficiency.. All the other given drugs dont undergo Hoffman elimination. From KD Tripati 7th edition Page no 253 