MRCEM Notes

Overdose and poisoning: management

The table below outlines the main management for common overdoses:

ToxinTreatment
ParacetamolManagement
  • activated charcoal if ingested < 1 hour ago
  • N-acetylcysteine (NAC)
  • liver transplantation
SalicylateManagement
  • urinary alkalinization is now rarely used - it is contraindicated in cerebral and pulmonary oedema with most units now proceeding straight to haemodialysis in cases of severe poisoning
  • haemodialysis
Opioid/opiatesNaloxone
BenzodiazepinesFlumazenil
Tricyclic antidepressantsManagement
  • IV bicarbonate may reduce the risk of seizures and arrhythmias in severe toxicity
  • arrhythmias: class 1a (e.g. Quinidine) and class Ic antiarrhythmics (e.g. Flecainide) are contraindicated as they prolong depolarisation. Class III drugs such as amiodarone should also be avoided as they prolong the QT interval. Response to lignocaine is variable and it should be emphasized that correction of acidosis is the first line in management of tricyclic induced arrhythmias
  • dialysis is ineffective in removing tricyclics
LithiumManagement
  • mild-moderate toxicity may respond to volume resuscitation with normal saline
  • haemodialysis may be needed in severe toxicity
  • sodium bicarbonate is sometimes used but there is limited evidence to support this. By increasing the alkalinity of the urine it promotes lithium excretion
WarfarinVitamin K, prothrombin complex
HeparinProtamine sulphate
Beta-blockersManagement
  • if bradycardic then atropine
  • in resistant cases glucagon may be used
Ethylene glycolManagement has changed in recent times
  • ethanol has been used for many years
  • works by competing with ethylene glycol for the enzyme alcohol dehydrogenase
  • this limits the formation of toxic metabolites (e.g. Glycoaldehyde and glycolic acid) which are responsible for the haemodynamic/metabolic features of poisoning
  • fomepizole, an inhibitor of alcohol dehydrogenase, is now used first-line in preference to ethanol
  • haemodialysis also has a role in refractory cases
Methanol poisoningManagement
  • fomepizole or ethanol
  • haemodialysis
Organophosphate insecticidesManagement
  • atropine
  • the role of pralidoxime is still unclear - meta-analyses to date have failed to show any clear benefit
DigoxinDigoxin-specific antibody fragments
IronDesferrioxamine, a chelating agent
LeadDimercaprol, calcium edetate
Carbon monoxideManagement
  • 100% oxygen
  • hyperbaric oxygen
CyanideHydroxocobalamin; also combination of amyl nitrite, sodium nitrite, and sodium thiosulfate
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