Overdose and poisoning: management

The table below outlines the main management for common overdoses:

Toxin _ Treatment| Paracetamol _ Management

• activated charcoal if ingested < 1 hour ago
• N-acetylcysteine (NAC)
• liver transplantation|

Salicylate _ Management

• urinary alkalinization with IV bicarbonate
• haemodialysis|

Opioid/opiates _ Naloxone| Benzodiazepines _ Flumazenil The majority of overdoses are managed with supportive care only due to the risk of seizures with flumazenil. It is generally only used with severe or iatrogenic overdoses.| Tricyclic antidepressants _ Management

• 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|

Lithium _ Management

• 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|

Warfarin _ Vitamin K, prothrombin complex| Heparin _ Protamine sulphate| Beta-blockers _ Management

• if bradycardic then atropine
• in resistant cases glucagon may be used|

Ethylene glycol_Management 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 poisoning_ Management

• fomepizole or ethanol
• haemodialysis|

Organophosphate insecticides_Management

• atropine
• the role of pralidoxime is still unclear - meta-analyses to date have failed to show any clear benefit|

Digoxin _ Digoxin-specific antibody fragments| Iron _ Desferrioxamine, a chelating agent| Lead _ Dimercaprol, calcium edetate| Carbon monoxide _ Management

• 100% oxygen
• hyperbaric oxygen|

Cyanide _ Hydroxocobalamin; also combination of amyl nitrite, sodium nitrite, and sodium thiosulfate|