What Causes Dark Urine While On Warfarin?

Posted on Wed, 9 Sep 2015

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Wed, 9 Sep 2015 Answered on

Tue, 29 Sep 2015 Last reviewed on

Question : I'm taking warfarin and recently I've been told that my figure is high (3.6-4) but now I am passing darker urine and need to go more frequently. Could this be caused by the warfarin. I'm away from home in Hong Kong right now so have no access to my regular doctor.

Answered by Dr. Ilir Sharka (20 minutes later)

Brief Answer:
I recommend stopping warfarin and going to the ER for some tests

Detailed Answer:
Hello!

Thank you for asking on HCM!

I understand your concern and would explain that the darker urine may be a sign of hemorrhage, related to an over dosage of warfarin and high values of INR.

I recommend stopping taking warfarin and going to the ER for a careful physical examination and some tests:

- a complete blood count
- a blood test for INR and Prothrombin time
- an urine analysis
- an abdominal ultrasound (to examine the urinary tract).

You should and discuss with the ER doctor on the proper warfarin dosage that you need to take in the next days (based on the above tests results).

Hope to have been helpful!

Feel free to ask any other questions whenever you need!

Best wishes,

Dr. Iliri

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar