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Tricyclic antidepressant overdose — SCE Acute Medicine MCQ

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ModerateToxicology and OverdoseTricyclic antidepressant overdoseSCE Acute Medicine

A 52-year-old woman presents after taking amitriptyline. She is agitated, hypotensive and has a generalised seizure in the resuscitation room. ECG shows QRS duration 148 ms and right axis deviation. ABG shows pH 7.28. What is the most appropriate next step in management?

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Correct answer: B — Give intravenous sodium bicarbonate and treat seizures with benzodiazepines

Tricyclic overdose with QRS widening, seizures and hypotension is managed with sodium bicarbonate to reduce sodium-channel blockade, plus benzodiazepines for seizures. Flumazenil can worsen seizures and is inappropriate in mixed or proconvulsant overdose. Verapamil and beta-blockers may worsen cardiovascular collapse. The pearl is that QRS duration is a toxicity marker and treatment target.

Reference: TOXBASE; BNF poisoning summary