Overdose and poisoning

Question 1

Paracetamol

Answer 1

• Activated charcoal if <1 hour ago
• NAC
• Liver transplantation

Question 2

Salicyclate

Answer 2

• 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

Question 3

Opioid/ opiate

Answer 3

Naloxone

Question 4

Benzodiazepines

Answer 4

Flumenezil

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.

Question 5

TCAs

Answer 5

• IV sodium 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

Question 6

Lithium

Answer 6

• mild to moderate toxicity may respond to volume resuscitation with normal saline
• haemodalysis in severe toxicity
• sodium bicarbonate is sometimes used but there is limited evidence to support this. By increasing the alkalinity of urine it promotes lithium excretion

Question 7

Warfarin

Answer 7

Vit K, prothrombin complex

Question 8

Heparin

Answer 8

Protamine sulphate

Question 9

Beta blockers

Answer 9

If bradycardic then atropine, in resistant cases, glucagon may be used.

Question 10

Ethylene glycol

Answer 10

• Ethanol has been used for many years; works by competing for binding site on alcohol dehydrogenase, limiting the formation of toxic metabolites (e.g. glycoaldehyde, glycolic acid) responsible for the haemodynamic and metabolic features of poisoning
• fomepizole; inhibits alcohol dehydrogenase is now used firstline
• haemodialysis for refractory cases

Question 11

Methanol poisoning

Answer 11

• fomepizol or ethanol

- haemodialysis

Question 12

Organophosphate poisoning

Answer 12

• atropine

- role of pralidoxime is still unclear (meta analysis to date have failed to show any benefit)

Question 13

Digoxin

Answer 13

Digoxin-specific antibody fragments

Question 14

Iron

Answer 14

Desferrioxamine, a chelating agent

Question 15

Lead

Answer 15

Dimercaperol, calcium edetate

Question 16

Carbon monoxide

Answer 16

• 100% oxygen

- Hyperbaric oxygen

Question 17

Cyanide

Answer 17

Hydroxocobalamin; also combination of amyl nitrite, sodium nitrite, and sodium thiosulfate