In older adults with atrial fibrillation or heart failure, which statement about digoxin is correct?

• A. Should be used as first-line for atrial fibrillation.
• B. Should be used as first-line for heart failure to reduce mortality.
• C. If used for atrial fibrillation or heart failure, dosages > 0.125 mg/day should be avoided.
• D. It is avoided entirely in older adults.

Answer: (C)

Digoxin has a very narrow therapeutic window and older adults often have reduced kidney function and multiple medications, which raise the risk of toxicity. For atrial fibrillation, digoxin can help slow the heart rate, but it isn’t the first-line choice since other drugs (like beta-blockers or certain calcium channel blockers) are typically preferred for rate control. For heart failure, digoxin may relieve symptoms and reduce hospitalizations, but it does not reduce mortality, so it isn’t a first-line life-extending therapy. Because of these risks, if digoxin is used in older adults, keeping the dose at or below 0.125 mg per day is advised to minimize toxicity. Some patients with very reduced renal function may require even lower dosing and close monitoring of kidney function and electrolytes. This is why the statement about avoiding higher doses aligns with safer, guideline-consistent practice.