Lithium toxicity — RCPSC EM MCQ
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Correct answer: C — Give IV bicarbonate and reassess QRS serially
The best answer is “Give IV bicarbonate and reassess QRS serially”. Hypotension, seizure and QRS widening indicate severe TCA sodium-channel blockade. IV sodium bicarbonate is the immediate treatment, guided by serial ECG and biochemical reassessment, with benzodiazepines for seizures and vasopressor support if needed. Physostigmine and procainamide can worsen conduction; dialysis is ineffective for most TCA poisoning.
Reference: Ontario Poison Centre: Tricyclic antidepressant overdose approach: https://www.ontariopoisoncentre.ca/siteassets/pdfs/english/tricyclicoverdoseapproach.pdf