For older adults with nonvalvular atrial fibrillation or VTE, which medication is least preferred as initial anticoagulation due to higher major bleeding risk and similar or lower effectiveness compared with DOACs?

• A. Warfarin
• B. Apixaban
• C. Dabigatran
• D. Edoxaban

Answer: (A)

In older adults with nonvalvular atrial fibrillation or VTE, direct oral anticoagulants (DOACs) are generally favored over warfarin because they offer similar or better effectiveness with a lower risk of major bleeding, especially intracranial hemorrhage, and they don’t require the routine INR monitoring and frequent dose adjustments that come with warfarin. Warfarin carries more variability in anticoagulation levels due to interactions with many foods and drugs, which increases bleeding risk in the elderly. Because of these factors, starting anticoagulation with warfarin is considered less preferred when a DOAC is an appropriate option. The other choices—apixaban, dabigatran, and edoxaban—are DOACs and typically have more favorable bleeding profiles and comparable efficacy compared with warfarin, making them the preferred initial options in this population (with individual renal function and contraindications guiding the exact choice).