A farm labourer exposed to a carbamate insecticide presents with salivation, miosis, and fasciculations. Compared with organophosphate poisoning, which statement about carbamate poisoning is correct?

• A The enzyme-inhibitor complex ages irreversibly within hours
• B Butyrylcholinesterase levels remain normal throughout the illness
• C Atropine is ineffective because the receptor blockade is non-competitive
• D Cholinesterase inhibition is spontaneously reversible, so pralidoxime is usually unnecessary ✓

Explanation

Carbamates inhibit acetylcholinesterase by transient carbamylation of the serine site, which hydrolyses spontaneously within minutes to hours, so the clinical course is shorter and oximes are generally not required. There is no ageing process, unlike organophosphates where the phosphorylated enzyme becomes irreversibly resistant to reactivation. Atropine remains the mainstay of treatment, making option C false.

Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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