pralidoxime

Pralidoxime, also known as pralidoxime chloride or by the abbreviation 2-PAM, is an antidote used in the treatment of organophosphate poisoning. It is an oxime that reactivates acetylcholinesterase (AChE) that has been inhibited by organophosphate compounds. The reactivation process removes the phosphate group from the enzyme, restoring its ability to break down acetylcholine. The effectiveness of pralidoxime depends on the timing of administration, because the inhibited enzyme–organophosphate complex can undergo aging, after which reactivation is unlikely.

Pralidoxime is most effective against poisoning from organophosphates that phosphorolyze AChE, such as certain pesticides and nerve agents. It is typically used in conjunction with atropine to treat muscarinic symptoms and to improve neuromuscular function. The compound is generally less effective against some organophosphates and is not effective against carbamate cholinesterase inhibitors. It does not readily cross the blood–brain barrier, so its central nervous system effects are limited compared with peripheral actions.

Administration and safety considerations: pralidoxime is given by intravenous or intramuscular injection, with dosing regimens varying by exposure, agent, and clinical guidelines. A common approach is an initial dose followed by repeated dosing as needed based on patient response. Possible adverse effects include headache, dizziness, nausea, tachycardia, and hypersensitivity reactions, though serious events are uncommon. Caution is advised in patients with renal impairment and in those with known hypersensitivity to pralidoxime.