Lecture 18: Non-sync - treatment of poisoning

What are the four main principles of poisoning management?

Prevent absorption, give antidote, enhance elimination, supportive care

When is activated charcoal most effective?

Within 1 hour of ingestion

When is activated charcoal ineffective?

Metals (iron, lithium), alcohols, hydrocarbons, acids/alkalis

What is whole bowel irrigation (WBI) used for?

Sustained-release drugs, iron, late presentation (>2h), drug packets

What are the key features of paracetamol overdose?

Initially asymptomatic → later liver failure

What is the antidote for paracetamol overdose?

N-acetylcysteine (NAC)

When should paracetamol levels be measured?

≥ 4 hours post ingestion

What is the toxic mechanism in paracetamol overdose?

NAPQI formation (toxic metabolite of paracetamol) + glutathione depletion → liver damage

What are key features of aspirin overdose?

Hyperventilation, tinnitus, respiratory alkalosis + metabolic acidosis

How is aspirin overdose managed?

Sodium bicarbonate (urinary alkalinisation) ± dialysis

What are key features of opioid overdose?

Reduced consciousness, pinpoint pupils, respiratory depression

What is the antidote for opioid overdose?

Naloxone

What are key features of TCA overdose?

Anticholinergic effects + wide QRS, arrhythmias

What is the key treatment for TCA overdose?

Sodium bicarbonate

What is a depressant toxidrome?

CNS depression, hypoventilation, hypotension (e.g. opioids)

What is an anticholinergic toxidrome?

Hot, dry, tachycardic, confused (e.g. TCAs)

What is a cholinergic toxidrome?

Salivation, sweating, diarrhoea, bronchospasm (organophosphates)

How are organophosphate poisonings treated?

Atropine + pralidoxime

What is the key issue in carbon monoxide poisoning?

Reduced oxygen delivery despite normal O₂ sats

How is carbon monoxide poisoning treated?

High-flow oxygen

How are toxic alcohol poisonings (methanol/ethylene glycol) treated?

Fomepizole or ethanol + dialysis

What is the key treatment for severe lithium toxicity?

Haemodialysis

What is the key feature of SSRI overdose?

QT prolongation ± seizures

What is the first-line treatment for stimulant toxicity?

Benzodiazepines