Can taking warfarin for several years cause black outs?

Warfarin by itself would not cause blackouts. The underlying condition requiring warfarin is a more likely explanation for the symptom.

If you are taking warfarin for A fib or valvular heart issues Yes and talk to your Dr. as they may be a sign of oncoming stroke. Your body is talking to you. Listen and take good notes and share with your Dr. The two of you can then likely figure it out.

The Warfarin is not likely to cause blackouts but the underlying reason for taking the Warfarin may be the cause. Afib or cardiac arrhythmias may cause sudden drops in blood pressure causing loss of consciousness. You should definitely see a physician or cardiologist as soon as possible if this is happening to you.