A 74-year-old woman with chronic atrial fibrillation on digoxin presents with confusion, nausea, and visual halos. Her previously irregular pulse is now perfectly regular at 48 bpm. ECG shows atrial fibrillation with a uniform junctional escape rhythm. What is the specific antidote?

• A Intravenous calcium gluconate
• B Activated charcoal and observation alone
• C Intravenous phenytoin loading dose
• D Digoxin-specific Fab fragments ✓

Explanation

Regularization of chronic atrial fibrillation due to complete AV nodal block with a junctional escape rhythm is a classic sign of advanced digoxin toxicity, along with gastrointestinal and visual symptoms. Digoxin-specific antibody Fab fragments are the definitive antidote for severe poisoning with life-threatening arrhythmias, hyperkalemia, or hemodynamic instability. Calcium stabilizes the myocardium transiently but does not remove the drug, and phenytoin treats some digitalis-induced arrhythmias without reversing toxicity.

Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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