Poisoning

Question 1

Activated charcoal

Answer 1

Increases the surface area available for adsorption or chemical reactions. Used to treat poisoning and overdose following oral ingestion. Not suitable for strong acids or alkalis, cyanide, iron, lithium, arsenic, methanol, ethanol or ethylene glycol.

Question 2

N-acetylcysteine

Answer 2

Used primarily as a mucolytic agent and in the management of paracetamol overdose.

Question 3

Paracetamol poisoning

Answer 3

• Activated charcoal if ingested

- Consider N-Acetyl Cysteine if treatment line dictates

Question 4

Salicylate poisoning

Answer 4

• urinary alkalinisation 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 5

Opioid/opiates poisoning

Answer 5

naloxone

Question 6

Benzodiazepine poisoning

Answer 6

flumazenil

Question 7

Tricyclic antidepressant poisoning

Answer 7

• IV bicarbonate may reduce the risk of seizures and arrhythmias in severe toxicity
• arrhythmias: class 1a (eg. quinidine) and class 1 c antiarrhythmics (eg. fleicanide) 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 emphasised that correction of acidosis is the first line in the management of tricyclic induced arrhythmias.
• dialysis is ineffective in removing tricyclics

Question 8

Lithium poisoning

Answer 8

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

Question 9

Warfarin poisoning

Answer 9

• vitamin K

- prothrombin complex

Question 10

Heparin poisoning

Answer 10

• protamine sulphate

Question 11

Beta-Blocker poisoning

Answer 11

• if bradycardic the atropine

- in resistant cases glucagon may be used

Question 12

Ethylene glycol poisoning

Answer 12

• ethanol has been used for many years
• works by competing with ethylene glycol for the enzyme alcohol dehydrogenase
• this limits the formation of toxic metabolits (eg 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

Question 13

Methanol poisoning

Answer 13

• fomepizole or ethanol

- haemodialysis

Question 14

Organophosphate insectisides poisoning

Answer 14

• atropine

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

Question 15

Digoxing poisoning

Answer 15

• digoxin-specific antibody fragments

Question 16

Iron poisoning

Answer 16

• desferrioxamine (a chelating agent)

Question 17

Lead poisoning

Answer 17

• dimercaprol (calcium edetate)

Question 18

Cabon monoxide poisoning

Answer 18

• 100% oxygen

- hyperbaric oxygen

Question 19

Cyanide poisoning

Answer 19

• hydroxycobalamin (also a combination of amyl nitrite, sodium nitrite and sodium thiosulphate)