If you take warfarin, the pain reliever of choice is acetaminophen (Tylenol®).


Eat a consistent, well-balanced diet while taking warfarin.


After you stop taking warfarin, it may take several days before your blood clotting ability returns to normal.


Warfarin (Jantoven®) is a blood thinner (or anticoagulant) that decreases the ability of your blood to form clots.

You should wear a medical alert bracelet while you take warfarin. Ask your health care provider for information on ordering one.


It is important to avoid activities that may cause injury and bleeding.

  • Use an electric shaver instead of a blade to avoid cutting yourself when you shave.
  • Use a soft-bristled toothbrush and floss gently to avoid bleeding gums.
  • Tell your health care provider if you have a dental or medical procedure planned. You may need to adjust your dosage for a short period of time.

Diet information

While taking warfarin, it is important to watch what you eat and drink. Foods that are rich in vitamin K can affect the way warfarin works in your body. Vitamin K helps your blood make clots while warfarin thins your blood.

Green leafy vegetables (such as broccoli, cabbage, collard greens, spinach, kale and some lettuce) and oils (canola, olive and soybean) have large amounts of vitamin K.

Keep your diet consistent with the amount of vitamin K you eat. This way your body will maintain a steady blood level of warfarin. Talk to your health care provider about a full list of foods that have vitamin K.

Some vitamins (vitamin E), herbs (St. John's wort) and supplements (ginger, ginseng and garlic) can change the effects of warfarin.

Important: Do not add or stop taking supplements while you are taking warfarin unless you have talked with your health care provider.

Check with your health care provider before using any of the following medicines because they will increase your risk of bleeding:

  • alcohol
  • cimetidine (Tagamet®)
  • some antibiotics (such as Septra® or Bactrim® (sulfamethoxazole and trimethoprim), Flagyl® (metronidazole), Diflucan® (fluconazole), Cipro® (ciprofloxacin) or Biaxin® or Biaxin XL® (clarithromycin)
  • aspirin
  • nonsteroidal anti-inflammatories (Motrin®, Advil®, Nuprin® (ibuprofen); Aleve® (naproxen); and Voltaren® or Cataflam® (diclofenac)

Side effects

Call your health care provider if you have any unusual bleeding or bruising, abdominal pain that won't go away or dark urine or dark stools.

Other side effects include:

  • headache
  • dizziness
  • weakness
  • unusual nosebleeds
  • throwing up blood

Blood test

The international normalized ratio (INR) blood test measures the time it takes your blood to clot. You will need to take this test on a regular basis. The results of the test will tell your health team members if your warfarin dose needs to be changed.

Write your dose of warfarin and the results of your lab tests on your daily log or calendar. Write any missed doses as well.

It is a good idea to wear an identification bracelet that says you take warfarin.

Related resources

Source: Allina Health's Patient Education Department, Heart Failure, fifth edition, 1-931876-31-2
First Published: 10/04/2002
Last Reviewed: 12/10/2015