Management of Drug Poisoning

General Principles - Poisoning Protocol Primer

⭐ In any suspected poisoning, always secure Airway, Breathing, and Circulation (ABC) first.

• Overall Management Flow:

• Systematic Approach (ABCDE):

  • Airway: Secure patency.
  • Breathing: Assess, support ventilation.
  • Circulation: IV access, manage shock.
  • Disability: Neurological status (GCS), glucose, consider naloxone/thiamine.
  • Exposure/Environment: Undress, decontaminate skin, control temperature.

• Further Management Principles:

  • History & Toxidrome Identification: Crucial for diagnosis and guiding therapy.
  • Decontamination: ↓ absorption (Activated Charcoal common; lavage/WBI for specific, early cases).
  • Antidotes: Specific agents if available and indicated (e.g., N-acetylcysteine for paracetamol).
  • Enhanced Elimination: Consider for severe, life-threatening cases (e.g., hemodialysis for salicylates, methanol).
  • Supportive Care: Treat complications (seizures, arrhythmias, electrolyte imbalance).
  • Observation & Disposition: Including psychiatric assessment for intentional poisoning.

Decontamination & Elimination - Detox Drilldown

• GIT Decontamination:
  • Gastric Lavage (GL): Within 1 hr post-ingestion; large bore tube. C/I: Corrosives, hydrocarbons, ↓LOC.
  • Activated Charcoal (AC): 1 g/kg (adults/children) within 1 hr. MDAC for enterohepatic/enteroenteric recirculation (e.g., phenobarbital, carbamazepine, dapsone, quinine, theophylline).

    ⭐ AC ineffective for: Pesticides, Heavy metals & Hydrocarbons, Alcohols, Acids & Alkalis, Iron, Lithium, Solvents (📌 PHAILS).

  • Whole Bowel Irrigation (WBI): PEG solution (1-2 L/hr adults, 25-40 mL/kg/hr children). For SR preps, body packers, Fe, Li.
• Enhanced Elimination:
  • Forced Alkaline Diuresis: IV NaHCO₃ to urine pH 7.5-8.5. For weak acids (salicylates, phenobarbital).
  • Hemodialysis (HD): For toxins with low Vd (<1 L/kg), low protein binding, high water solubility. 📌 I STUMBLE (Isopropanol, Salicylates, Theophylline, Uremia, Methanol, Barbiturates (long), Lithium, Ethylene glycol).
  • Hemoperfusion (HP): Blood via adsorbent column. For high protein binding or lipid soluble toxins (e.g., theophylline, paraquat).

Specific Antidotes - Antidote All-Stars

• Paracetamol: N-acetylcysteine (NAC). Replenishes glutathione.

  ⭐ N-acetylcysteine (NAC) is most effective for paracetamol poisoning when administered within 8-10 hours of ingestion.

• Opioids: Naloxone. Competitive opioid antagonist.
• Benzodiazepines: Flumazenil. (⚠️ Risk of seizures in chronic users or TCA co-ingestion).
• Organophosphates/Carbamates: Atropine (muscarinic effects); Pralidoxime (PAM) (cholinesterase reactivator, ⚠️ not for carbamates).
• Warfarin: Vitamin K (slow); FFP/PCC (rapid).
• Heparin: Protamine sulfate.
• Iron: Deferoxamine (chelator).
• Lead: EDTA, DMSA (Succimer), Dimercaprol (BAL).
• Cyanide: Hydroxocobalamin; Sodium nitrite + Sodium thiosulfate.
• Methanol/Ethylene glycol: Fomepizole (preferred); Ethanol.
• Beta-blockers: Glucagon; High-dose insulin.
• Calcium Channel Blockers: Calcium salts; Glucagon; High-dose insulin.
• Digoxin: Digoxin-specific antibody fragments (DigiFab).
• Isoniazid (INH): Pyridoxine (Vitamin B6).
• Carbon Monoxide (CO): 100% $O_2$; Hyperbaric $O_2$ (HBO).
• Methemoglobinemia: Methylene blue (⚠️ G6PD deficiency).
• TCAs: Sodium bicarbonate (QRS widening).

Toxidromes - Syndrome Sleuthing

• Key symptom clusters for poison classes. Aids rapid diagnosis.
• Opioid: Miosis, ↓RR, ↓CNS.
• Sympathomimetic: Mydriasis, agitation, ↑HR, ↑BP, ↑Temp, diaphoresis.
• Anticholinergic: Mydriasis, dry/hot/flushed skin, delirium, urinary retention. 📌 (Classic "mad hatter" mnemonic).
• Cholinergic: Miosis, ↑secretions (saliva, tears), GI upset (diarrhea, emesis), urination.
• Sedative-Hypnotic: ↓CNS, slurred speech, ataxia.
• Serotonin: Mental status Δ, autonomic hyperactivity, clonus.

⭐ The cholinergic toxidrome mnemonic DUMBELS (Diarrhea/Diaphoresis, Urination, Miosis, Bronchorrhea/Bronchospasm, Emesis, Lacrimation, Salivation) is frequently tested.

High‑Yield Points - ⚡ Biggest Takeaways

• Prioritize ABCDE approach for initial stabilization in all poisonings.
• Gastric lavage is time-sensitive, effective mainly within 1 hour post-ingestion.
• Activated charcoal is widely used; ineffective for iron, lithium, alcohols, corrosives, hydrocarbons.
• Specific antidotes: Naloxone (opioids), Flumazenil (benzodiazepines), N-acetylcysteine (paracetamol).
• Enhanced elimination: Forced alkaline diuresis (salicylates, phenobarbital), Hemodialysis (lithium, methanol, ethylene glycol).
• Identify the toxidrome to guide empirical treatment and antidote selection.