Organophosphate compounds covalently phosphorylate acetylcholinesterase, abolishing acetylcholine hydrolysis and flooding cholinergic synapses. Management has two prongs: symptomatic control with atropine (a muscarinic antagonist that dries secretions and corrects bradycardia) and causal reversal of the enzyme block.
Enzyme reactivation is achieved only by an oxime. $Pralidoxime$ carries a quaternary nitrogen that aligns it near the anionic site and a nucleophilic oxime group that attacks the phosphorus, regenerating free, functional AChE:
\[ \text{Inhibited AChE-P} + \text{2-PAM} \rightarrow \text{Active AChE} + \text{Phosphorylated oxime} \]
This particularly rescues nicotinic (muscle weakness, fasciculations) signs that atropine cannot touch. Efficacy falls once the phosphoryl-enzyme complex "ages."
Flumazenil (benzodiazepine antagonist) and naloxone (opioid antagonist) act on unrelated receptors and have no role here.
\[\boxed{\text{Pralidoxime}}\]