Pralidoxime (2-PAM) is best described as what in organophosphate poisoning?

• A. A reactivator of acetylcholinesterase
• B. A muscarinic antagonist
• C. An acetylcholinesterase inhibitor
• D. A benzodiazepine

Answer: (A)

Restoring acetylcholinesterase activity after organophosphate inhibition is the main idea here. Pralidoxime (2-PAM) reactivates the enzyme by binding to the phosphorylated acetylcholinesterase and cleaving the bond formed by the organophosphate, freeing the enzyme to break down acetylcholine again. This reversal reduces the excess cholinergic signaling that drives the symptoms, especially the peripheral effects. Timing matters because as the enzyme–organophosphate complex ages, reactivation becomes unlikely, so earlier administration is more effective. Pralidoxime is not a muscarinic antagonist (it doesn’t block receptor signaling), it is not an acetylcholinesterase inhibitor (that would worsen inhibition), and it isn’t a benzodiazepine (it doesn’t act on GABA receptors). Note that its ability to reach the central nervous system is limited, so it mainly helps with peripheral symptoms while other treatments may address central effects or seizures as needed.