Drug OverdoseDRUG OVERDOSEManagement Principles and

Decontamination

HistorySpeak 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

InvestigationABG

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

TreatmentComa 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 EvidencePosition 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 IISchedule 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