Overdose Flashcards
What resource is good to look up management of OD?
TOXBASE
Paracetamol OD causes the build up of what toxic metabolite?
NAPQI
Define a staggered OD
OD taken over >1 hour
What amount of paracetamol = significant toxicity?
> 150 mg/kg
Give 2 factors increasing the risk of liver damage in paracetamol OD
Malnutrition and alcohol (previous damage)
How may paracetamol OD present (<24 hours)
Nausea, vomiting, sweating
abdo pain?
What are the late signs of paracetamol OD? (i.e. if untreated)
Liver failure!!
Jaundice, confusion, coagulopathy, hypoglycaemia
After 3-5 days
When should you measure plasma levels of paracetamol
After 4 hours
If someone presents <1 hour post-paracetamol OD, what can you give them?
Activated charcoal 1g/kg
What do you give for paracetamol OD as soon as you get the 4 hour reading back?
NAC (N-acetylcysteine)
When is NAC most effective?
<8 hours
How is NAC given?
24 hour infusion
How does NAC work?
Increases the amount of glutathoine so NAPQI can be broken down
Do you still give NAC if paracetamol OD presents late?
YES!!
Someone presents 8-24 hours post-paracetamol OD - what do you give them?
NAC straight away!
If the amount is >150mg/kg, even before the serum conc comes back
How do you manage a staggered OD?
Give NAC immediately if amount >150 mg/kg - serum levels not reliable in this context
What triclyclic is most likely to cause lethal intoxication?
1st generation (e.g. amitriptyline)
What are the anti-cholinergic features of tricyclic OD?
these present early
Dry mouth Dilated pupils Tachycardia Urinary retention Myoclonic jerks Blurred vision Hypotension
Is the response in tricyclic OD sympatetic or parasympathetic?
SYMPATHETIC response because it blocks parasympathetic
What are the effects of blocking sodium channels in tricyclic OD?
Cardiac arrhythmias + seizures
What are the features of severe tricyclic OD?
coma, respiratory depression, hypoxia, metabolic acidosis
What amount of tricyclic can cause death?
1000mg
ECG changes in tricyclic OD
Broad QRS (seen before ventricular arrhythmias occur) Tachycardia Torsardes de pointes
What would an ABG indicate in tricyclic OD?
metabolic acidosis
What is the general approach to any OD?
ABCDE!
What is the initial management of tricyclic OD if there are ECG changes?
IV sodium bicarbonate!!
for prolonged QRS
What would you do if someone presents <1 hour of tricyclic OD with NO ECG changes?
Gastric lavage/ activated charcoal (50g)
N.B. Always give the bicarb first if there are ECG changes
How would you treat seizures in tricyclic OD?
IV benzos
e.g. 5-10mg diazepam
If arrhythmias persist after giving bicarb, what else can be given?
lidocaine
Give 2 examples of amphetamines
MDMA
Speed
How does amphetamine OD present? (sympathomimetic)
Dilated pupils
Hyperthermia
Hypertension
Hyperthermia
How does amphetamine OD present? (central effects)
Agitation
Paranoia
Seizures
Give complications of amphetamine OD
intracranial haemorrhage
Vasospasm
DIC
AKI
What is creatinine kinase a sign of in tricyclic/ amphetamine OD?
Rhabdomyolysis
What body temperature is a poor progostic factor in amphetamine OD?
Hyperpyerxia >42
What would you give to control seizures/ agitation in amphetamine OD?
5-10mg diazepam or 1-2mg lorazepam
In amphetamine OD what would you give if someone is psychotic?
Haloperidol
In amphetamine OD, if indicated how would you manage temperature control?
Cool with sponge /chilled IV fluids
Chlorpromazine: can help lower temp, may lead to hypotension + sedation
How may somoene with opiate OD present?
Pinpoint pupils Reduced RR Drowsiness Cyanosis Coma
What common feature of opiate OD can cause AKI?
Rhabdomyolysis
What is the drug for opiate OD?
NALOXONE (opiate antagonist)
how is naloxone given?
0.4mg at 2-3 minute intervals until the patient is rousable + resp distress is corrected
Why are repeat injections of naloxone required?
It has a shorter half life than opioids (can be given as IV infusion)
What problem may occur if giving naloxone to someone who is opiate-dependant?
How would you manage this?
Could precipitate an acute withdrawal reaction
(avoid giving enough to completely reverse opiate effects)
Diazepam
How may salicylate OD present? (ears!)
Tinitus
If someone presents within 1 hour of salicylate OD, what can be given?
Charcoal
What can be given in salicylate OD?
Sodium bicarb
What is the treatment of choice in severe salicylate poisoning?
Haemodialysis
What is the reversal agent for benzodiazepine (e.g. diazepam) OD?
Flumazenil
Why shouldn’t flumazenil be given if benzo OD is mixed with tricyclics?
Flumazenil lowers the seizure threshold
What is the king’s college criteria for liver transplant?
FOR PARACETAMOL OVERDOSE!! Arterial pH <7.3 after 24 hours OR all 3 of: PT >100 Creatinine >300 Encephalopathy
