A 14-year-old girl is brought after ingesting an unknown quantity of amitriptyline. She is drowsy with a GCS of 10. ECG shows sinus tachycardia at 130/min, QRS duration of 120 ms, and a terminal R wave in aVR. Which of the following is the most appropriate immediate treatment?
- A IV flumazenil 0.2 mg
- B IV lidocaine 1 mg/kg
- C IV sodium bicarbonate 1-2 mEq/kg bolus ✓
- D IV magnesium sulfate 25 mg/kg
Correct answer: C. IV sodium bicarbonate 1-2 mEq/kg bolus
Explanation
Tricyclic antidepressant overdose causes sodium channel blockade producing QRS widening (>100 ms), terminal R wave in aVR, and ventricular arrhythmias. Sodium bicarbonate is the antidote: it provides sodium to overcome channel blockade and alkalemia reduces free drug. Flumazenil is for benzodiazepines and can precipitate seizures. Lidocaine is second-line. Magnesium is for torsades.
Reference: Goldfrank's Toxicologic Emergencies, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.