DRUG OVERDOSE

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• DRUG OVERDOSE
• Management Principles

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History

• Speak to
• patient
• relatives
• ambulance officers
• Ask
• what drug was ingested
• when
• how much

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Examination

• LOC ? GCS
• Vital signs
• Temp/PR/BP/RR/SpO2
• 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

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Investigation

• BSL
• mandatory if ? LOC
• ECG
• always done
• findings very specific
• QRS complex
• indicative of Na channel blockade if prolonged

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Investigation

• Normal QRS is lt 100 ms
• QT interval
• lt420 ms male lt440 children lt450 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 lt70 or gt50

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Investigation

• Concentrations are useful if suggestion of
  poisoning with
• salicylates
• paracetamol
• lithium
• valproate
• theophylline

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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

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Investigation

• Miscellaneous
• CXR if aspiration suspected
• CT brain if story not c/w clinical findings
• CK if unconscious for some time

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• 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
• RISK ASSESSMENT

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Treatment

• May be specific antidote
• Paracetamol
• Tricyclic antidepressants
• Verapamil/Diltiazem
• Methanol/Ethylene Glycol

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• May be general/empiric
• Decontamination
• generous IV fluid replacement
• ? Coma cocktail

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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

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Decontamination

• Syrup of Ipecac
• Gastric lavage
• Activated charcoal
• multi dose
• with cathartic
• Whole bowel irrigation

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Activated charcoal

• Will adsorb many toxins in GI tract BUT
• Alcohols
• Li, Fe 2 (probably all alkali metals)
• Evidence from volunteer studies that absorption
  will be ? if lt 60 min.s
• Little to suggest benefits outcome clinically or
  absorption post 60 min.s
• DO NOT GIVE ROUTINELY

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Multi dose activated charcoal

• Works by
• GI dialysis
• drugs with significant enterohepatic circulation
• examples
• theophylline
• anticonvulsants
• salicylates

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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

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Whole bowel irrigation

• PEG ELS (go-lytely) is used frequently causes
  vomiting, requires NGT
• airway must be protected
• dose is 15-20 mls/kg/hr
• endpoint is clear rectal effluent, median time to
  achieve this is 6 hours

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• A 50 kg female presents having ingested 6 g of
  paracetamol 5 hours previously
• Syrup of Ipecac
• Gastric lavage
• Gastric Lavage AC
• Gastric lavage Whole bowel lavage
• AC
• Whole Bowel Lavage
• None

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• A 70 kg male presents having ingested 14 g
  paracetamol 3 hours before
• Syrup of Ipecac
• Gastric lavage
• Gastric Lavage AC
• Gastric lavage Whole bowel lavage
• AC
• Whole Bowel Lavage
• None

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• A 70 kg male presents having ingested 14 g
  paracetamol 1 hour before
• Syrup of Ipecac
• Gastric lavage
• Gastric Lavage AC
• Gastric lavage Whole bowel lavage
• AC
• Whole Bowel Lavage
• None

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• A 45 kg female presents having ingested 2 g of a
  tricyclic antidepressant 1 hour before
• Syrup of Ipecac
• Gastric lavage
• Gastric Lavage AC
• Gastric lavage Whole bowel lavage
• AC
• Whole Bowel Lavage
• None

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• A 50 kg male presents unconscious having ingested
  an unknown amount of a tricyclic antidepressant
  at an unknown time
• Syrup of Ipecac
• Gastric lavage
• Gastric Lavage AC
• Gastric lavage Whole bowel lavage
• AC
• Whole Bowel Lavage
• None

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• A 67 kg male presents having ingested 800 mg of a
  tricyclic antidepressant 6 hours before. He is
  well.
• Syrup of Ipecac
• Gastric lavage
• Gastric Lavage AC
• Gastric lavage Whole bowel lavage
• AC
• Whole Bowel Lavage
• None

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• A 80 kg male presents having ingested 100 mg of
  diazepam 4 hours before
• Syrup of Ipecac
• Gastric lavage
• Gastric Lavage AC
• Gastric lavage Whole bowel lavage
• AC
• Whole Bowel Lavage
• None

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• A 65 kg female presents having ingested 3.5 g of
  Verapamil SR 4 hours before.
• Syrup of Ipecac
• Gastric lavage
• Gastric Lavage AC
• Gastric lavage Whole bowel lavage
• AC
• Whole Bowel Lavage
• None

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• A 45 kg female presents having ingested 10 g
  elemental iron 4 hours before.
• Syrup of Ipecac
• Gastric lavage
• Gastric Lavage AC
• Gastric lavage Whole bowel lavage
• AC
• Whole Bowel Lavage
• None

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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
• ? Section as per mental health act

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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