Anticoagulants

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

Types of anticoagulants

Anticoagulants that are taken as pills (oral) include:

  • 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.

Anticoagulants not currently funded but available in New Zealand include:

  • apixaban, also called Eliquis

How do they work?


Anticoagulants block the natural process of clotting, such as when you get a cut. 

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

Side effects

If you are on anticoagulants, you’re at greater risk of bleeding. Common side effects include increased bruising or bleeding. 

Call your doctor or Healthline (0800 611 116) if you have:

  • bleeding you cannot stop
  • blood in your urine (pee) or stools (poo)
  • coughing or vomiting blood
  • vomiting something that looks like coffee grounds 
  • unusually heavy periods
  • a large bruise that forms a lump (haematoma)
  • becoming very weak or tired, short of breath
  • a serious fall or bang to the head.

Some anticoagulants can cause indigestion, heartburn and upset stomachs. This usually goes away with time. 

Talk to your doctor if your side effects are worrying you. Don’t stop taking your medication without talking to your doctor first. It can increase your risk of blood clots and a heart attack or stroke.

What checks do I need?

Warfarin

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 Awanui Labs 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. 

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
  • medicines bought from a pharmacy without a prescription
  • natural medicines
  • vitamins
  • alternative therapies.

These can sometimes make your heart medications less effective or stronger.

Activities that can increase your risk of bleeding:

  • contact sport
  • tattoos and piercings
  • deep massage.

Foods that can impact the effectiveness of warfarin include:

  • foods high in vitamin K, such as liver, leafy vegetables like broccoli, spinach, kale and Brussels 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 and other health procedures, treatments or conditions

Anticoagulants make you bleed more, so tell 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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