Download Drug Overdose

Drug
Overdose
DRUG OVERDOSE
Management Principles and
Decontamination
History
Speak to:
 patient
 relatives
 ambulance officers
Ask
 what drug was ingested
 when
 how much
Examination
LOC  GCS
 uniformly used
 developed for prognosticating head injuries
 verbal and pain response most useful in
DSPs
• AVPU
Vital signs
 Temp/PR/BP/RR/SpO2
Examination
Mini-Neuro
 Pupil size and reaction
 Reflexes
 Gross assessment of muscle tone
Chest/CVS as appropriate but low yield
BS may be  in anticholinergic toxidrome
Investigation
BSL
 mandatory if  LOC
ECG
 always done
 findings very specific
QRS complex
 indicative of Na+ channel blockade if
prolonged
Investigation

Normal QRS is < 100 ms
QT interval
 <420 ms male <440 children <450 female
 may be prolonged in certain poisonings
 neuroleptics esp. thioridazine
QT or QTc ?
 Standardises QT to a rate of 60 bpm
 only useful if heart rate <70 or >50
Investigation
Concentrations are useful if suggestion of
poisoning with
 salicylates
 paracetamol
 lithium
 valproate
 theophylline
No use as a screening tool
Investigation
ABG
Useful in assessing ventilatory status
Useful if ingestion can cause metabolic upset:
(VBG)
 salicylate
 metformin
OR
 if patient needs serum or urinary
alkalinisation
Investigation
Miscellaneous:
 CXR if aspiration suspected
 CT brain if story not c/w clinical findings
 CK if unconscious for some time
 K+ in digoxin poisoning
 Close
attention to ABC and
supportive care is all that is
required to manage MOST drug
overdoses
 GCS/vital signs/mini neuro and
ECG are only tests/investigations
likely to alter management with
a few notable exceptions
Treatment
May be specific antidote
 NAC in paracetamol poisoning
May be general/empiric
 decontamination
 coma cocktail
 generous IV fluid replacement
Treatment
Coma cocktail
 Dextrose/Thiamine/Naloxone/Flumazenil
Problems
 hypoglycaemia  can be assessed with BM
stix
 Naloxone  can precipitate acute
withdrawal
 Flumazenil  may complicate further
seizure management
Decontamination
When should patient be decontaminated?
risk of morbidity and/or mortality associated
with ingestion
What type of decontamination should be
used?
Depends on clinical circumstances and other
treatment options
Decontamination



Syrup of Ipecac
Gastric lavage
Activated charcoal
• multi dose
• with cathartic

Whole bowel irrigation
Where is the Evidence ?
Based on
 Animal studies
 Volunteer studies
 clinical studies
Difficulty due to
 serious ingestions excluded
 conflicting results
Where is the Evidence
Position statements released in 1997 by
AACT and EAPCCT
“Overall the mortality from acute poisoning is
less than 1 % and the challenge for
clinicians is to identify promptly those who
are at most risk of developing serious
complications and who might potentially
benefit, therefore, from gastrointestinal
decontamination.”
Syrup of Ipecac

Plant extract previously abused by bullimics
 needs to be given EARLY
 induces vomiting by gastric and central
mechanism
Contraindicated in
 unprotected airway
 corrosive
 very little evidence for or against
 possible role in the home for children
Gastric lavage

No studies demonstate efficacy even < 60
min.s
 Studies exclude serious poisonings
Contraindicated:
 dodgy airway reflexes
 corrosives
 hydrocarbon
Gastric lavage

May increase risk of aspiration
 May lead to pharyngeal injury
 alleged to increase absorption in some cases
 Has lead to significant return of ingestants
up to 12 hours post ingestion(salicylates)
Indication
 Serious life threatening poisoning with
well protected airway
(level IV evidence)
Activated charcoal

Will adsorb many toxins in GI tract BUT:
• Alcohols
• Li+, Fe 2+ (probably all alkali metals)



Ratio should be 10:1 AC:toxin
Evidence from volunteer studies that
absorption will be  if < 60 min.s
Little to suggest benefits outcome clinically
or absorption post 60 min.s
DO NOT GIVE ROUTINELY
Activated charcoal

Beware the unprotected airway or aspiration
risk
 dose is 50g adult, 1g/kg in a child
Cathartics
 Alleged to increase bowel transit time of
toxin
 Evidence only from animal and volunteer
studies
 Unlikely to benefit
Multi dose activated charcoal

Works by
• GI dialysis
• drugs with significant enterohepatic circulation

examples:
•
•
•
•
theophylline
anticonvulsants
salicylates
digoxin
Multi dose activated charcoal




Good, though indirect evidence of effect in
digoxin poisoning
50g q 6 hrly OR by NG infusion if intubated
up to 1g/kg suggested for serious
theophylline poisonings
Justifies “late” instigation of charcoal
Whole bowel irrigation
Used for
 SR/EC preparations
 when charcoal is ineffective
 No controlled clinical studies to back up use
physically speeds up transit through GI tract
single dose charcoal given prior to starting
Whole bowel irrigation






PEG ELS (“go-lytely”) is used  does not
cause significant water/electrolyte
disturbance
frequently causes vomiting, requires NGT
airway must be protected
ileus is CI but has been reversed with
neostigmine
dose is 15-20 mls/kg/hr
endpoint is clear rectal effluent, median
time to achieve this is 6 hours
Duty of Care


Ingestion of an overdose renders a patient
incompetent
If requires hospitalisation for physical
effects of drug overdose
• keep under duty of care

If no medical issues and attempts to leave

Schedule II
Take home messages




History, focused exam and a few tests,
supportive care +/- period of observation is
appropriate management for most DSPs
Ipecac is never used, gastric lavage
occasionally
Charcoal is only given if likely to benefit
Patients receiving decontamination must
have airway protection