Question 276

Question:

A patient with heart and renal failure presents to the emergency department complaining of a three-week history of palpitations and progressively deteriorating vision. Laboratory tests are notable for a potassium of 3.2 and a calcium of 11.0. Which of the following drugs most likely accounts for her symptoms?

Correct Answer: B.  Digoxin

Digoxin is a cardiac glycoside classically used to treat congestive heart failure, but has been largely replaced in recent years due to its narrow therapeutic window. Xanthopsia (yellowing and/or blurring of vision) and cardiac dysrhythmias are common side effects of digoxin toxicity. The incidence of digoxin toxicity is elevated in patients with hypokalemia and hypercalcemia, as these conditions enhance the activity of digoxin.

Captopril is an angiotensin converting enzyme (ACE) inhibitor and is not associated with vision changes or cardiac dysrhythmias.

Esmolol is a beta-adrenergic receptor antagonist (beta blocker) used most frequently in emergency situations due to its rapid onset and short duration of action. While beta blockers can induce cardiac dysrhythmias, they are not associated with vision deterioration.

Nifedipine and verapamil are calcium channel blockers. They are commonly administered for hypertension and angina pectoris, not congestive heart failure.