Tricyclic Antidepressant Poisoning — Management Pathway

Step-by-step decision

Choose step by step as prompted; reaching an endpoint gives the management recommendation. You can go back a step or restart anytime.

🎓 Want to practice? Do a case challenge with this pathway → (get a case, choose management step by step, scored).

Full pathway

1. [Decision] Cardiotoxicity?
   Cardiotoxicity / QRS widening? (Tricyclics (amitriptyline, etc.) block sodium channels → QRS widening (>100 ms predicts seizures, >160 ms predicts ventricular arrhythmia), an R wave in aVR; with anticholinergic features (mydriasis, tachycardia, dry flushed skin, delirium), alpha-blockade hypotension, seizures, coma. Judge by ECG and clinical features; drug levels are of limited value.)
   • QRS >100 ms / ventricular arrhythmia / hypotension → Cardiotoxicity → bicarbonate
   • No cardiotoxicity, alert → No cardiotoxicity · observe
2. [End] No cardiotoxicity · observe
   Normal QRS, alert: monitor (ECG, mentation), serial ECGs (may be delayed), activated charcoal (if early and airway protected, 1 g/kg); escalate immediately if QRS widens/seizures/hypotension appear.
3. [End] Cardiotoxicity → bicarbonate
   1) Sodium bicarbonate (the key antidote): QRS >100 ms, ventricular arrhythmia or severe hypotension → 1–2 mEq/kg IV push, repeat until QRS narrows; target blood pH 7.50–7.55 (sodium load + alkalinization reverses sodium-channel blockade), monitor pH/sodium/potassium. 2) Seizures: benzodiazepines first-line (avoid phenytoin — worsens sodium-channel blockade; flumazenil is contraindicated with co-ingested benzodiazepines). 3) Hypotension: crystalloid → refractory uses a direct-acting vasopressor (norepinephrine/phenylephrine). 4) Arrhythmia: add bicarbonate first, lidocaine if refractory; avoid class Ia/Ic agents, beta-blockers, amiodarone. 5) Refractory: lipid emulsion, ECMO. 6) Physostigmine is contraindicated. ICU monitoring.

Source guidelines & references

• Tricyclic / sodium-channel-blocker toxicity (LITFL ECG Library; EMCrit IBCC)

This pathway is our own synthesis of the decision logic in the guidelines above (not the guideline verbatim); thresholds and workflows change as guidelines update — in practice follow the latest guideline, your institution's protocol and the individual patient.

Other pathways