skip to main content

Tricyclic antidepressant poisoning — RCPSC EM MCQ

Instant feedback + full explanation. One question, done properly.

HardToxicologyTricyclic antidepressant poisoningRCPSC EM

A 19-year-old student is found obtunded after an intentional ingestion. Temperature is 38.7°C, heart rate is 142/min, QRS is 132 ms and blood pressure is 86/50 mmHg. Pupils are dilated, skin is dry and there are recurrent self-terminating wide-complex runs on the monitor. What is the most appropriate next step?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Give IV sodium bicarbonate boluses and start aggressive supportive care

Tricyclic antidepressant poisoning causes sodium-channel blockade with QRS widening, hypotension and ventricular dysrhythmia. IV sodium bicarbonate is first-line for cardiotoxicity; physostigmine is unsafe in this context.

Reference: Goldfrank's Toxicologic Emergencies; Canadian poison centre practice