A 75-year-old male with atrial fibrillation, heart failure with preserved ejection fraction (HFpEF), and chronic constipation is taking apixaban 5 mg BID, furosemide 40 mg daily, and diltiazem 180 mg daily. He complains of increasing fatigue and shortness of breath over the past month. Lab results show Hb 95 g/L (baseline 120 g/L 6 months ago) and a normal ferritin. Which medication is most likely contributing to his new symptoms and anemia?

Question: A 75-year-old male with atrial fibrillation, heart failure with preserved ejection fraction (HFpEF), and chronic constipation is taking apixaban 5 mg BID, furosemide 40 mg daily, and diltiazem 180 mg daily. He complains of increasing fatigue and shortness of breath over the past month. Lab results show Hb 95 g/L (baseline 120 g/L 6 months ago) and a normal ferritin. Which medication is most likely contributing to his new symptoms and anemia?

Answer options: ✅ Apixaban

• Furosemide
• Diltiazem
• All medications are contributing equally

Correct answer: Apixaban

Explanation: Apixaban is an anticoagulant, and while effective for atrial fibrillation, can cause gastrointestinal or other occult bleeding, leading to iron deficiency anemia over time. Fatigue and shortness of breath are symptoms consistent with anemia. The normal ferritin makes acute blood loss less likely, but chronic low-grade bleeding from anticoagulation could lead to this presentation.