A 70-year-old woman on digoxin and furosemide presents with nausea, confusion, and sees halos around lights described as yellow-green. ECG shows frequent ventricular ectopics and serum potassium is 3.0 mEq/L. The most appropriate definitive treatment is:

• A Intravenous potassium chloride alone
• B Oral cholestyramine to bind enteric digoxin
• C Digoxin-specific antibody fragments (Fab) ✓
• D Intravenous magnesium sulfate followed by amiodarone loading

Explanation

Xanthopsia, gastrointestinal symptoms, and ventricular ectopy in a patient on digoxin indicate digoxin toxicity, and life-threatening arrhythmias are treated with digoxin-specific Fab fragments, which bind free digoxin and promote urinary excretion. Hypokalemia from furosemide potentiates toxicity by reducing competition for Na/K ATPase. Potassium correction alone is adjunctive and insufficient when serious arrhythmia is present. Cholestyramine interrupts enterohepatic cycling but is far too slow for unstable toxicity.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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