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Are you on blood thinners?

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Are you on blood thinners? Do you see red?

Many people on blood thinner medications will experience visible blood in the urine that is severe enough to require medical attention, a new study published in JAMA has found.

What are blood thinners? Antithrombotics – also called blood thinners – include anticoagulants and antiplatelets.

Blood thinners are often prescribed to people with heart disease, or those who are at risk of blood clots or stroke.

Antiplatelet drugs, such as aspirin, prevent blood cells called platelets from joining together to form a clot.

Anticoagulants, such as warfarin, lengthen the time it takes to form a blood clot.

2.5 Million: The study looked at the data of 2.5 million Ontarians over a 13-year study period. 800,000 people were prescribed antithrombotic medication during the study period. For those who had been on blood thinners, 123 per 1000 people had visible blood in their urine. The bleeding was severe enough to require medical intervention like a procedure, ER visit or hospital stay.

Older men are more at risk of severe bleeding requiring a trip to the emergency room.

Unmasking a silent cancer: The study also showed blood thinners unmasked the presence of silent bladder cancer (due to the bleeding) at a rate that was more than twice that of the general population.

What does this mean?

  • Blood in your urine can cause distress and further complications, like infections and kidney failure.
  • If you have blood in your urine, don’t delay. Talk to your doctor.
  • Talking about this with your doctor can help reduce the risk of requiring medical intervention or a hospital stay.


Find out more.

Read the full study.

Bladder Cancer Canada.


About the author


Alexis Dobranowski

Alexis Dobranowski is a Communications Advisor at Sunnybrook.