Doxacurium chloride (formerly recognized as BW938U80 or BW A938U) is a neuromuscular-blocking drug or skeletal muscle relaxant in the category of non-depolarizing neuromuscular-blocking drugs, used adjunctively in anesthesia for endotracheal intubation or to facilitate mechanical ventilation. Unlike a number of other related skeletal muscle relaxants, it is rarely used adjunctively to facilitate endotracheal intubation. Doxacurium chloride is a mixture of three trans, trans stereoisomers, a dl pair [(1R,1'R ,2S,2'S ) and (1S,1'S ,2R,2'R )] and a meso form (1R,1'S,2S,2'R). NUROMAX binds competitively to cholinergic receptors on the motor end-plate to antagonize the action of acetylcholine, resulting in a block of neuromuscular transmission. This action is antagonized by acetylcholinesterase inhibitors, such as neostigmine.