A quaternary ammonium ion that is N-ethyl-N,N-dimethylanilinium in which one of the meta positions is substituted by a hydroxy group. It is a reversible inhibitor of cholinesterase, with a rapid onset (30-60 seconds after injection) but a short duration of action (5-15 minutes). The chloride salt is used in myasthenia gravis both diagnostically and to distinguish between under- or over-treatment with other anticholinesterases. It has also been used for the reversal of neuromuscular blockade in anaesthesia, and for the management of poisoning due to tetrodotoxin, a neuromuscular blocking toxin found in puffer fish and other marine animals. ChEBI: Edrophonium is a quaternary ammonium ion that is N-ethyl-N,N-dimethylanilinium in which one of the meta positions is substituted by a hydroxy group. It is a reversible inhibitor of cholinesterase, with a rapid onset (30-60 seconds after injection) but a short duration of action (5-15 minutes). The chloride salt is used in myasthenia gravis both diagnostically and to distinguish between under- or over-treatment with other anticholinesterases. It has also been used for the reversal of neuromuscular blockade in anaesthesia, and for the management of poisoning due to tetrodotoxin, a neuromuscular blocking toxin found in puffer fish and other marine animals. It has a role as an EC 3.1.1.8 (cholinesterase) inhibitor, a diagnostic agent and an antidote. It is a quaternary ammonium ion and a member of phenols.