Drug Over Dose

Question 1

Paracetamol

Management (3)

Answer 1

1. activated charcoal if ingested < 1 hour ago
2. N-acetylcysteine (NAC)
3. liver transplantation

Question 2

Kings College Liver Transplant Criteria

or
-
AND BOTH FROM
-
-

If not paracetamol induced
-
or 3 from:
1.
2.
3.
4.
5.

Answer 2

Paracetamol induced:
-Arterial pH< 7.3, 24hrs after ingestion
or
- PT time > 100s/ INR >6.5
AND
- Creatinine > 300
- Grad III or IV encephalopathy

If not paracetomal induced
- PT time > 100s
or 3 from:
1. Drug induced liver failure
2. Age =< 10yo or >=40yo
3. 1 week from first jaundice encephalopathy
4. PT time > 30s
5. Bilirubin >= 300

Question 3

Salicylate (2)

Answer 3

Management
1. urinary alkalinization with IV bicarbonate
2. haemodialysis

Question 4

Opioid/opiates (1)

Answer 4

Naloxone

Question 5

Benzodiazepines

Answer 5

Majority are management conservatively
this is due to the risk of seizures with flumazenil (benzo anatagonist)

generally only used with severe or iatrogenic overdoses.

Question 6

Warfarin (2)

Answer 6

Vitamin K, prothrombin complex

Question 7

Tricyclic antidepressants
Management
1….. + why?
Why should…. antiarrythmias be CI/ avoided
-
-
-
2. Lignocaine is variable,correction of acidosis is the first line in management of tricyclic induced arrhythmias

….. Is ineffective

Answer 7

1. IV bicarbonate- to recude seizure risk and arrythmias

Why should…. antiarrythmias be CI/ avoided
- class 1a (e.g. Quinidine) - prolong depolarisation
- class Ic (e.g. Flecainide)- prolong depolarisation
- . Class III amiodarone- prolong the QT interval.

2. Lignocaine is variable,correction of acidosis is the first line in management of tricyclic induced arrhythmias

dialysis Is ineffective!

Question 8

Lithium
where is it metabolized?
- Therefore key!!

mil-mod =

severe =

some evidence for…. + why?

Answer 8

• In kidneys
• Take into account in AKI

mild-moderate- may respond to volume resuscitation with normal saline

severe = haemodialysis

sodium bicarbonate is sometimes used but there is limited evidence to support this.

By increasing the alkalinity of the urine it promotes lithium excretion

Question 9

Heparin (1)

Answer 9

Protamine sulphate

Question 10

Beta-blockers

• if bradycardic
• if resistant then…

Answer 10

if bradycardic then atropine

in resistant cases glucagon may be used

Question 11

AKI

What drugs are nephrotoxic and should be stopped? (6)

What drugs are renally excreted and need to be monitored? (3)

What drug should be adapted/ changed? (1)

Answer 11

Nephrotoxic
1. ACEi
2. ARB
3. Aminoglycosides- eg. gentamicin
4. Diuretics
5. NSAIDs (not cardiac 70mg dose)
6. Iodine contrast

Renally excreted
1. Metformin
2. Lithium
3. Digoxin

Adapt- Opioids

Question 12

Ethylene glycol
- where do you find this?

1. • MOA?
2. If refractory-

EXtra- used to use…

Answer 12

• anti-freeze

1. Fomeprizole- Inhibits alcohol dehydrogenase therefore prevents metaboliation an acetaldehyde toxicity build up
2. If refractory- haemodialysis

Previously- ethanol as a competitive inhibitor, competing with ethylene glycol for the enzyme alcohol dehydrogenase-

limits the formation of toxic metabolites (e.g. Glycoaldehyde and glycolic acid) which are responsible for the haemodynamic/metabolic features of poisoning

Question 13

Methanol poisoning
1…. or ….
2.

Answer 13

Management
1. fomepizole or ethanol
2. haemodialysis

Question 14

Organophosphate insecticides
1.
2 – iffy

Answer 14

Management
1. atropine

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

Question 15

Digoxin (1)

Answer 15

Digoxin-specific antibody fragments

Question 16

Iron

Answer 16

1. Desferrioxamine, a chelating agent

Question 17

Lead
1.
2.

Answer 17

Dimercaprol
calcium edetate

Question 18

Carbon monoxide
1
2

Answer 18

Management
1. 100% oxygen
2. hyperbaric oxygen

Question 19

Cyanide
1.

Answer 19

Hydroxocobalamin (synthetic Vit B12) ; also combination of amyl nitrite, sodium nitrite, and sodium thiosulfate