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Anticoagulants medicines (often called 'blood thinners') reduce your risk of blood clots. Read about types of anticoagulants, how they work, and their side effects.

Types of anticoagulants

Anticoagulants in tablet form (oral) include:

  • apixaban, also called Eliquis
  • dabigatran, also called Pradaxa
  • rivaroxaban, also called Xarelto
  • warfarin, also called Coumadin, Marevan

Anticoagulants given by injection (either self-administered or given by a health professional):

  • enoxaparin, also called Clexane
  • heparin.

How do they work?

Anticoagulants make your blood take longer to clot. This reduces your risk of heart attacks, strokes or other conditions caused by blood clots.

Side effects

If you're on anticoagulants, you’re at a greater risk of bleeding. Common side effects include:

  • increased bruising
  • prolonged nosebleeds
  • bleeding gums
  • heavy periods.

If you experience any of the following, see your health professional:

  • blood in your urine (wee)
  • blood in your stools (poo)
  • coughing up blood
  • vomiting blood
  • haematoma (a large bruise that forms a lump).

Ring 111 if you have any of the following:

  • severe chest pain
  • severe headache
  • sudden shortness of breath
  • sudden weakness or numbness in your face, arm or leg
  • difficulty speaking, jumbled words or lose your voice
  • swelling of your mouth, lips or tongue, as this could be an allergic reaction.

It may take a while for the medication to work. Talk to your doctor if your side effects are worrying you. Don’t stop taking your medication without talking to your doctor first. The benefits usually outweigh the side effects.

What checks do I need?


You’ll need regular blood tests to check how long it takes for your blood to clot. This test is called an INR blood test. It can be done at your closest Labtests branch, some GP surgeries, and some local pharmacies.

When you first start warfarin it can take days, or even weeks, to get the correct dose for you. 


Wafarin and your diet

Dabigatran, apixaban and rivaroxaban

You don't need to have your blood clotting checked for these medications. You will have a blood test every 6 to 12 months to check your kidneys.

What happens if I miss a dose?

If you forget to take a dose, take it immediately, then continue as normal the following day. However, if it’s almost time for the next dose, skip the missed dose and continue as normal.

Do NOT take a double dose.

What else do I need to know when taking anticoagulants?

Tell your health professionals if you’re taking any:

  • supplements
  • natural medicines
  • vitamins
  • alternative therapies.

These can sometimes make your heart medications less effective.

Foods that can impact the effectiveness of warfarin include:

  • foods high in vitamin in K, such as leafy vegetables like broccoli, spinach, kale and brussel sprouts
  • cranberries or cranberry juice
  • alcohol
  • soya beans
  • canola oil.

Talk to your doctor, nurse or pharmacist for more guidance on your intake of these items if you're on warfarin.

Anticoagulants extend the length of time you bleed, so you should inform other health professionals such as dentists, midwives and podiatrists before you have any procedure or treatment.

Talk to your doctor about pregnancy or breastfeeding if you're on anticoagulants and these apply to you.

You may like to consider getting a Medic Alert bracelet or carrying an identification card.

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