What precautions can you take against warfarin side effects?

To reduce your chance of developing warfarin side effects:

  • Tell your doctor about any other medications or supplements you take. Many medications and supplements can have a dangerous interaction with warfarin. If you receive a new prescription from someone other than your usual care provider, ask if you'll need additional blood tests to make sure the new medication isn't affecting your blood clotting.
  • Tell care providers you take warfarin before you have any medical or dental procedures. It's important to share this information even before minor procedures, such as vaccinations and routine dental cleanings. If you're going to have surgery, you may need to decrease or discontinue your warfarin dose at least five days before the procedure. Your doctor might prescribe a shorter acting blood thinner, heparin, while you're not taking warfarin.
  • Avoid situations that increase your risk of injury. Contact sports and other activities that could result in head injury should be avoided. Tell your doctor if you are unsteady while walking or have a history of falling.
  • Use safer hygiene and grooming products. A soft-bristle toothbrush, waxed dental floss and an electric razor for shaving can help prevent bleeding.
  • Consider wearing a bracelet or carrying a card that says you take warfarin. This identification can be useful if emergency medical providers need to know what medications you take.
  • Consider a warfarin sensitivity test. A significant number of people who take warfarin are at a higher risk of bleeding because their genes make them more sensitive to warfarin. If a family member experienced side effects from warfarin, talk to your doctor about taking a genetic warfarin sensitivity test. The test can determine if you have the genes that can increase your risk of bleeding.

What drugs and supplements can interact with warfarin?

Like any other medication, warfarin can interact with foods, other drugs, vitamins or herbal supplements. The interaction might lower the effectiveness of warfarin or increase your risk of bleeding. More than 120 drugs and foods that can interact with warfarin have been identified.

Drugs that can interact with warfarin include:

  • Many antibiotics
  • Antifungal medications, such as fluconazole (Diflucan)
  • Aspirin or aspirin-containing products
  • Ibuprofen (Advil, Motrin, others) or naproxen sodium (Aleve, Anaprox)
  • Acetaminophen (Tylenol, others) or acetaminophen-containing products
  • Cold or allergy medicines
  • Medications that treat abnormal heart rhythms, such as amiodarone (Cordarone, Pacerone)
  • Antacids or laxatives

Many other medications interact with warfarin. Be sure to tell any health care provider or pharmacist that you take warfarin.

Supplements that can interact with warfarin include:

  • Coenzyme Q10 (ubidecarenone)
  • Dong quai
  • Garlic
  • Ginkgo biloba
  • Ginseng
  • Green tea
  • St. John's wort
  • Vitamin E

Many other supplements can interact with warfarin. Be sure to tell your health care provider about any supplements you take.

What foods and drinks might interact with warfarin?

Foods and drinks that might interact with warfarin include:

  • Cranberries or cranberry juice
  • Alcohol
  • Foods that are high in vitamin K, such as soybean and canola oils, spinach and broccoli
  • Garlic
  • Black licorice

Your doctor might recommend keeping the level of vitamin K in your diet consistent rather than avoiding vitamin K-rich foods altogether.

What should you do if you forget a dose?

Never take a double dose of warfarin. Doing so could greatly increase your risk of side effects.

If you miss a dose, take it as soon as you remember. If you don't remember until the next day, call your doctor for instructions. If your doctor isn't available, skip the missed dose and start again the next day.

If you follow your doctor's dosing instructions and tell all your health care providers that you take warfarin, you'll be at a much lower risk of dangerous interactions and side effects. Talk to your doctor, nurse or pharmacist if you have any concerns about warfarin.

Jan. 06, 2015 See more In-depth