A 19-year-old student is brought to the emergency department after eating seeds offered by a stranger at a fair. He is agitated, flushed, has dry skin and mucosa, dilated pupils that do not react to light, tachycardia, and urinary retention. Which is the most appropriate specific antidote?
- A Neostigmine
- B Pralidoxime
- C Physostigmine ✓
- D Naloxone
Correct answer: C. Physostigmine
Explanation
The picture is classic anticholinergic (Datura, Atropa belladonna) poisoning: blind as a bat, hot as a hare, dry as a bone, red as a beet, mad as a hatter. Physostigmine, a tertiary amine anticholinesterase, crosses the blood-brain barrier and reverses both central and peripheral effects. Neostigmine is a quaternary amine that does not cross into the CNS, so it cannot treat the delirium, which kills the most tempting distractor.
Reference: Parikh's Textbook of Medical Jurisprudence, Forensic Medicine and Toxicology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.