<prompt> Which of the following muscle relaxant has the maximum duration of action -AtracuriumVecuroniumRocuroniumDoxacurium  <response>: Ans. is d i.e., Doxacurium o Amongst the given options doxacurium is longest acting Duration of action 90-120 minutes. Rocuronium duration of action 30-60 minutes, Atracurium duration of action 30-60 minutes and vecuronium duration of action 60-90 minutes have shoer duration of action than doxacurium. 