A 55-year-old woman with a history of atrial fibrillation managed with digoxin presents to the emergency department with a 2-day history of progressive nausea, vomiting, confusion, and yellow-green halos around lights. She reports recently starting hydrochlorothiazide for hypertension two weeks ago. Vitals: BP 98/62 mmHg, HR 52 bpm and irregularly irregular, RR 16, Temp 37°C, SpO2 98% on room air. Physical examination reveals mild diffuse abdominal tenderness and disorientation to time. ECG demonstrates new-onset second-degree AV block with frequent premature ventricular contractions. Serum digoxin level is 2.8 ng/mL (therapeutic range 0.5–2.0 ng/mL); serum potassium is 3.2 mEq/L; creatinine is 1.9 mg/dL. She denies chest pain or dyspnea. Which of the following is the most appropriate next step in management?

1. A)Switch immediately to amiodarone without washout period
2. B)Continue current dose but monitor renal function as the primary intervention
3. C)Perform gastric lavage and administer activated charcoal to reduce drug absorption
4. D)Administer digoxin-specific antibody fragments (Fab) and check serum electrolytes, especially potassiumGABARITO
5. E)Increase the digoxin dose to achieve better rate control and therapeutic drug levels