Cardiovascular Drugs USMLE Step 1 Practice Question
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?
Answer choices
- ASwitch immediately to amiodarone without washout period
- BContinue current dose but monitor renal function as the primary intervention
- CPerform gastric lavage and administer activated charcoal to reduce drug absorption
- DAdminister digoxin-specific antibody fragments (Fab) and check serum electrolytes, especially potassiumCorrect answer
- EIncrease the digoxin dose to achieve better rate control and therapeutic drug levels
- FAdminister intravenous calcium gluconate to stabilize the cardiac membrane and correct hypokalemia with potassium supplementation
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