Tox Tute: Tricyclic Antidepressant Overdose

A young male is unconscious and on his way to your hospital. Bystanders confirm he has been depressed and taken an overdose. The paramedics are worried about his ECG…”it looks weird and his QRS is very wide”. The following tox tute will guide you through managing this patient.

ECG on arrival
TCA-toxicity
Tox Tute TCA Basic
AUDIO: TCA Overdose – Quick Version

Tox Tute TCA Advanced
AUDIO: TCAs Overdose
VIDEO: Pharmacology of TCAs BSCC
VIDEO: TCAs and the ECG

Essential Knowledge

Key TCA knowledge:

  • >10mk/kg is potentially life threatening
  • Severe toxicity usually manifests within 2 hours
  • QRS widens due to fast sodium channel blockade, >100ms is predictive of seizures and >160ms is predictive of ventricular tachycardia
  • The mainstay of treatment for severe toxicity involves aggressive supportive care including the use of sodium bicarbonate for dysrhythmias and widening of the QRS alongside hyperventilation to maintain a pH >7.5-7.55

Additional Resources


toxicology library antidote 700 1

Toxicology Library

BASICS

Dr Neil Long BMBS FACEM FRCEM FRCPC. Emergency Physician at Burnaby Hospital in Vancouver. Loves the misery of alpine climbing and working in austere environments. Supporter of FOAMed, toxicology, tropical medicine, sim and ultrasound

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