A 71-year-old man is brought to the emergency department by his wife because of increasing confusion, weakness, and vomiting for 1 day. He has had 5 episodes of vomiting and blurry vision; he told his wife that "everything appears in different colors." His wife reports that his drug regimen was adjusted because of worsening tibial edema 1 week ago. He has congestive heart failure, hypothyroidism, and osteoarthritis. Current medications include metoprolol, digoxin, levothyroxine, spironolactone, and furosemide. His temperature is 36.7°C (98°F), pulse is 56/min, and blood pressure is 98/68 mm Hg. He is confused and oriented only to person. Neurologic examination shows no focal findings. The abdomen is soft, and there is tenderness to palpation of both lower quadrants without guarding or rebound. Age-related changes in which of the following factors most likely accounts for this patient's symptoms?

Question

Quizplus · Accepted Answer

Eductional Objective: Digoxin is a cardiac glycoside that is predominantly cleared by the kidneys.  Elderly patients typically exhibit age-related renal insufficiency, even in the presence of normal creatinine levels.  The dose of digoxin must be reduced in these patients to prevent toxicity.

A 71-Year-Old Man Is Brought to the Emergency Department by His