Identify the drug from the list below that is not classified as a non-depolarizing competitive neuromuscular blocking agent.

Explanation

Doxacurium, Rocuronium, and Mivacurium are all non-depolarizing competitive neuromuscular blockers used to induce muscle relaxation. Decamethonium, however, is a depolarizing neuromuscular blocker and does not act through competitive inhibition, distinguishing it from the others listed.