Toxicology [advanced]

Common toxidromes

Management

General management

• Activated charcoal (50g drink)
  • Can be given in overdoses <1 hour of ingestion (<4 hours if tricyclic) to reduce absorption of many orally ingested toxins
  • Only if patient can swallow properly (must have GCS 15)
  • NOT FOR: acids&alkalis, alcohols, metals, organic solvents 
• Supportive ABCDE-style management is the major part of management for most overdoses is continuous, supportive ABCDE-style management
  • A: recovery position, airway adjuncts
  • B: oxygen, treat hypoventilation
  • C: cardiac monitor, IV fluids to maintain BP, treat brady/tachycardias (bicarbonate for acidosis)
  • D: diazepam for seizures, treat hypo/hyperthermia
• Control adverse effects e.g. seizures
• Haemofiltration may be required (lithium, salicylate, ethanol, ethylene glycol, methanol)

Specific antidotes

A database (e.g. Toxbase) should be used to guide specific management (but examples for common overdoses are below)

• Paracetamol → N-acetylcysteine
• Morphine → Naloxone
• Beta-blocker → Atropine, glucagon
• Benzodiazepam → Flumazenil (NOT given for overdoses – risk of seizures)
• Digoxin → Digibind
• Warfarin → Vitamin K, prothrombin complex concentrate
• Heparin → Protamine sulphate
• Carbon monoxide → high-flow oxygen
• Volatile solvents → Methylene blue for slate-grey cyanosis
• Iron → Deferoxamine
• Sulfonylurea → Octreotide
• Lead → Sodium calcium edetate
• Cyanide → Vitamin B12
• Copper → Penicillamine
• Methotrexate → Folinic acid (Leucovorin), glucarpidase
• Ethylene glycol or methanol (e.g. antifreeze) → Fomepizole (or, if unavailable, ethanol)
• Organophosphate (e.g. pesticide) → Atropine, pralidoxime

Psychological management (in deliberate overdose)

• Assess risk to self/others (consider section if tries to leave)
• Assess capacity if tries to abscond or refuses treatment
• Psychiatric referral

Common overdoses

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What characteristic ECG changes may be seen in digoxin toxicity?

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List three toxins that cause a raised anion gap metabolic acidosis

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