Blood in the Urine in Patients on Anticoagulants

Andrew Siegel MD  6/16/2018


TY, Pixabay, for image above

Many people take blood thinners to prevent clotting complications that may occur as a result of cardiac arrhythmias—particularly atrial fibrillation, cardiac valvular disease; cardiomyopathy, mechanical heart valves, as well as for treatment or prevention of venous clotting and pulmonary embolism. Visible urinary bleeding is not uncommon in patients on anticoagulants, especially under the circumstance of being “over”-anti-coagulated.  Anticoagulants per se do not usually cause urinary bleeding, but if there is an underlying urinary tract abnormality they can provoke and perpetuate the bleeding.  Thus the importance of doing an evaluation to search for an underlying cause of the urinary tract bleeding.

Commonly used anticoagulants (blood thinners)

  • Fragmin (dalteparin)
  • Lovenox (enoxaparin)
  • Heparin
  • Coumadin (warfarin)
  • Eliquis (apixaban)
  • Pradaxa (dabigatran)
  • Xarelto (rivaroxaban)
  • Plavix (clopidogrel)
  • Brilinta (ticagrelor)


Medical speak for blood in the urine is hematuria.  When blood can be seen it is called gross hematuria, although I prefer the term visible hematuria. Visible hematuria may cause red urine if the bleeding is fresh or tea or cola-colored urine if the bleeding is old. Sometimes hematuria is accompanied by blood clots. At times hematuria is only evident by seeing bloodstains on one’s underwear or appearing on toilet tissue after wiping.

Most hematuria is painless. When there is pain associated with hematuria, it is often a symptom of a kidney stone or urinary infection. Like a nosebleed, hematuria can be a non-significant problem due to a ruptured blood vessel, or alternatively, it can be due to a serious issue that mandates treatment, such as a kidney or bladder cancer, which are  two of the most serious causes of hematuria. Those who use or who have used tobacco and have hematuria have a much higher risk of bladder  and kidney cancer than non-tobacco users. The most common cause of hematuria in men is benign prostate enlargement (as the prostate grows, so does the blood supply) and the most common cause in women is a urinary infection.

Hematuria can occur after vigorous exercise, particularly in people who have bladder stones or an underlying structural abnormality of the urinary tract. Hematuria can be a side effect occurring many years following pelvic radiation to treat cancers of the bladder, prostate, rectum, uterus, cervix, etc.

What to do If you experience urinary tract bleeding while anti-coagulated:

  1. Inform your doctor who prescribed the anticoagulant and  ensure that you are on the appropriate dosage.
  2. If the bleeding is severe enough, it may be necessary to temporarily halt the use of the anticoagulant. Make sure this decision is discussed with the doctor who prescribed the anticoagulant.
  3. Restrict exertional activities and straining with bowel movements and any other activity that may exacerbate the bleeding.
  4. Step up your fluid intake to dilute the urine and promote passage of blood clots.
  5. See your urologist to be properly evaluated.

How hematuria is evaluated

Urine Cytology:  Pap smear of a specimen of urine that looks for abnormal cells.

Urine Culture: Lab test to see if a urinary infection is present.

Imaging Tests: Ultrasound, computerized tomography (CT), magnetic resonance imaging (MRI) and cystoscopy with contrast injected into the ureters to image the inner aspects of the upper urinary tract (retrograde studies) are all possibilities.

Cystoscopy: A visual inspection of the bladder with a narrow, flexible instrument performed on a video monitor with magnification.

Bottom Line:  Regardless of whether or not you are anti-coagulated, never ignore blood in urine, whether visible or microscopic (seen on a urinalysis test).  It may be “nothing” (not a sign of a serious illness) or may be “something” (a warning sign of a potentially life-threatening illness), so it is always beneficial to seek proper evaluation.  If you experience hematuria while anti-coagulated, do not assume that it is an expected consequence of the medication, since there may be serious underlying problems that are “provoked” or “unmasked” by the anticoagulant. Do not panic since the cause can usually be readily determined and treatment initiated; even if the precise cause cannot be pinpointed, serious underlying causes can be excluded.

Wishing you the best of health,

2014-04-23 20:16:29

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Dr. Andrew Siegel is a physician and urological surgeon who is board-certified in urology as well as in female pelvic medicine and reconstructive surgery.  He is an Assistant Clinical Professor of Surgery at the Rutgers-New Jersey Medical School and is a Castle Connolly Top Doctor New York Metro Area, Inside Jersey Top Doctor and Inside Jersey Top Doctor for Women’s Health. His mission is to “bridge the gap” between the public and the medical community.

Dr. Siegel has authored the following books that are available on Amazon, iBooks, Nook and Kobo:

MALE PELVIC FITNESS: Optimizing Sexual & Urinary Health

THE KEGEL FIX: Recharging Female Pelvic, Sexual and Urinary Health 

PROMISCUOUS EATING: Understanding and Ending Our Self-Destructive Relationship with Food


These books are written for educated and discerning men and women who care about health, well-being, fitness and nutrition and enjoy feeling confident and strong.

Dr. Siegel is co-creator of the male pelvic floor exercise instructional DVD (female version is in the works): PelvicRx


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