A 70-year-old woman on digoxin for chronic AF presents with nausea, yellow-tinged vision, and confusion. ECG shows frequent ventricular bigeminy and a new regular narrow-complex tachycardia at 150 bpm with atrial rate 75 bpm. Serum potassium is 5.8 mEq/L. What is the definitive treatment?
- A IV potassium chloride replacement
- B Oral activated charcoal alone
- C Digoxin-specific antibody fragments (Fab) ✓
- D IV amiodarone infusion
Correct answer: C. Digoxin-specific antibody fragments (Fab)
Explanation
The findings are classic digoxin toxicity: gastrointestinal symptoms, xanthopsia, ventricular ectopy, and atrial tachycardia with AV block (atrial rate near 75 with fixed 2:1 conduction). Definitive therapy is digoxin-specific Fab fragments, indicated whenever life-threatening arrhythmia, significant hyperkalemia, or severe toxicity is present. Giving extra potassium is dangerous because toxicity itself impairs the sodium-potassium ATPase and raises serum potassium; hyperkalemia here reflects poisoning severity, not deficiency.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.