OLD MAN — O for OP (Atropine), L for Lead (EDTA), D for Dimercaprol (Arsenic/Mercury), M for Morphine (Naloxone), A for Acetaminophen (NAC), N for Nitrites (Cyanide)
Forensic Toxicology — Common Poisons & Antidotes
NEET-PGAIIMSFMGE
Items to Memorize
- Organophosphorus → Atropine + Pralidoxime (PAM)
- Arsenic → BAL (Dimercaprol)
- Lead → EDTA / Succimer
- Mercury → BAL / DMSA
- Cyanide → Sodium Nitrite + Sodium Thiosulphate
- Opioids → Naloxone
- Benzodiazepines → Flumazenil
- Paracetamol → N-Acetylcysteine (NAC)
- Iron → Desferrioxamine
- Warfarin → Vitamin K
- Heparin → Protamine Sulphate
Mnemonic Tricks
How It Maps
| Cue | Maps To |
|---|---|
| O (OP poisoning) | Organophosphorus → Atropine + PAM |
| L (Lead) | Lead → EDTA / Succimer |
| D (Dimercaprol) | Arsenic/Mercury → BAL |
| M (Morphine/opioid) | Opioids → Naloxone |
| A (Acetaminophen) | Paracetamol → NAC |
| N (Nitrite for cyanide) | Cyanide → Sodium Nitrite + Thiosulphate |
Why It Sticks
OLD MAN — picture a poisoned old man in a forensic case. Each letter of his name is a poison-antidote pair, covering the 6 most-tested combinations in NEET-PG.
An OLD farmer sprayed OP PESTICIDE (→ give Atropine to dry his secretions, PAM to reactivate enzymes). His LEADEN pipes (→ EDTA chelates the metal). The ARSENIC in his well (→ BAL/Dimercaprol grabs it). A CYANIDE pill (→ Nitrites + Thiosulphate convert it to harmless thiocyanate). He overdosed on MORPHINE (→ Naloxone reverses it). His PARACETAMOL headache cure became toxic (→ NAC restores glutathione).
Why It Sticks
A single forensic crime scene with each poison appearing logically — the story walks through mechanisms (Atropine dries secretions, chelators grab metals, NAC restores glutathione), not just names.
Frequently Asked Questions
What are the most important poison-antidote pairs for NEET-PG?
Top tested pairs: OP → Atropine+PAM, Lead → EDTA, Arsenic → BAL, Cyanide → Sodium Nitrite+Thiosulphate, Opioids → Naloxone, Paracetamol → NAC, Iron → Desferrioxamine, Benzodiazepines → Flumazenil, Warfarin → Vitamin K, Heparin → Protamine.
What is the antidote for organophosphorus poisoning?
Atropine (antimuscarinic — dries secretions, reverses bradycardia) + Pralidoxime/PAM (reactivates acetylcholinesterase if given within 24-48 hours before 'aging' occurs).
How to remember forensic toxicology for exams?
Use 'OLD MAN' mnemonic for the 6 key pairs, then add: Iron=Desferrioxamine (iron DEFerred), BZD=Flumazenil (FLU reverses FLUffy sleepiness), Warfarin=Vitamin K (K for Klotting), Heparin=Protamine (PRO-tects against heparin).
What is BAL used for?
BAL (British Anti-Lewisite / Dimercaprol) is a chelating agent used for Arsenic, Mercury, Gold, and Lead poisoning. It binds heavy metals and promotes their excretion in urine.
What are the features of organophosphorus poisoning?
Remember DUMBELS: Diarrhoea, Urination, Miosis (pupil constriction), Bradycardia/Bronchospasm, Emesis, Lacrimation, Salivation. All due to excessive acetylcholine from cholinesterase inhibition.