Which is one of the main antidotes for organophosphate poisoning?

• A. Atropine
• B. Pralidoxime (2-PAM)
• C. Physostigmine
• D. Diazepam

Answer: (B)

Organophosphates block acetylcholinesterase, causing a buildup of acetylcholine that overstimulates muscarinic, nicotinic, and CNS receptors. The main antidote is pralidoxime (2-PAM) because it reactivates acetylcholinesterase by cleaving the organophosphate from the enzyme’s active site, restoring the enzyme’s function and reversing both peripheral and neuromuscular effects. Its effectiveness depends on prompt administration before aging of the enzyme–inhibitor complex. Atropine helps by blocking muscarinic receptors to reduce symptoms but does not restore the enzyme’s activity. Physostigmine would worsen toxicity since it inhibits acetylcholinesterase, and diazepam is used to control seizures rather than acting as a true antidote. In practice, treatment combines pralidoxime with atropine and supportive care.