A 62-year-old woman on digoxin for atrial fibrillation presents with nausea, yellow-tinged vision, and a ventricular bigeminy pattern on ECG. Serum potassium is 6.2 mEq/L and the digoxin level is markedly elevated. The definitive antidotal therapy is:

• A Digoxin-specific antibody Fab fragments ✓
• B Intravenous calcium gluconate
• C Oral potassium chloride replacement
• D Intravenous magnesium sulfate

Explanation

Life-threatening digitalis toxicity is treated with digoxin-specific Fab fragments, which bind free digoxin and are then renally cleared, reversing arrhythmias within hours. Hyperkalemia here reflects poisoning of the Na/K ATPase pump, not true potassium excess, so giving potassium is harmful. Intravenous calcium was historically feared to cause stone heart, though this concern has been largely debunked, but calcium treats hypocalcemic tetany, not glycoside toxicity. Magnesium is an adjunct for torsades, not the specific antidote.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.