Credits: Sandra Ponen, pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland
Last reviewed: 05 Aug 2018
Anticoagulants for atrial fibrillation
Deciding between warfarin, dabigatran and rivaroxaban
Until 2011, the most commonly prescribed oral anticoagulant in New Zealand was warfarin (known by the brand names Marevan and Coumadin). Since then, new oral anticoagulants have become available, such as dabigatran and more recently rivaroxaban.
These medicines work well at reducing the risk of blood clots, but they are slightly different.
Once it has been decided that you need anticoagulant treatment, discuss the best option with your doctor.
The following are some of the key points to discuss with your doctor and pharmacist to help you choose the anticoagulant most suitable for you and your situation.
Anticogulants: help me choose
Situations when warfarin may be preferred to dabigatran and rivaroxaban
Warfarin: You will take 1 or more tablets once a day, usually in the evening. The dose will be adjusted depending on blood test results (see below) and you will be given written instructions about how many tablets to take each day. Treatment with warfarin is normally long term.
Dabigatran: You will take 1 dabigatran capsule twice a day. You will most likely stay on the same dose all the time. Treatment is usually long term.
Rivaroxaban: You will take 1 rivaroxaban tablet once a day. You will most likely stay on the same dose all the time. Treatment is usually long term.
Will I need regular blood tests?
Warfarin: For the first few weeks and months, you will need frequent blood tests. After that, most people need to have blood tests every 1–2 months. Some people will need blood tests more or less often than this, and some people are able to test their blood themselves or at a community pharmacy.
Dabigatran: When you first start taking dabigatran, you will need blood tests to check how well your kidneys and liver are working. No regular blood testing to check the level of dabigatran is needed, but you may need to have occasional tests to check your kidneys and liver.
Rivaroxaban: When you first start taking rivaroxaban, you will need blood tests to check how well your kidneys and liver are working. No regular blood testing to check the level of rivaroxaban is needed but you may need to have occassional tests to check your kidneys and liver.
Will I have to change what I eat or drink?
Warfarin: This medicine interacts with alcohol and many common foods. Major changes in what you eat may affect how your body responds to warfarin. Avoid drinking cranberry juice and making any major changes to your diet without talking to your doctor or pharmacist first.
Dabigatran: There are no known food interactions, but it is best not to drink too much alcohol.
Rivaroxaban: There are no known food interactions, but it is best not to drink too much alcohol.
Will the medicine interact with other medicines I take?
All anticoagulants interact with many other medicines such as ibuprofen, diclofenac, aspirin and herbal supplements such as garlic, ginkgo, ginseng and St Johns Wort. This can mean your medicines won’t work the way they are meant to, or you may have more side effects. Check with your doctor or pharmacist before starting an anticoagulant or before starting any new medicines, including herbal medicines, vitamins and medicines that you buy yourself, such as pain relief medicine.
What about side effects?
All anticoagulants have side effects and can cause bleeding and bruising. Other common side effects include:
Warfarin: diarrhoea (runny poos), nausea (feeling sick), hair loss
Rivaroxaban: nausea (feeling sick), indigestion, tummy cramps and headache.
What about the risk of bleeding?
All anticoagulants have a risk of bleeding but, as compared with warfarin:
Dabigatran has more risk of stomach bleeding but less risk of bleeding in your brain (intracranial bleeding)
Rivaroxaban has more risk of stomach bleeding but less risk of bleeding in your brain.
What happens if I need non-urgent surgery, including dental surgery?
It is important to tell anyone treating you, including your dentist and physiotherapist, that you are taking an anticoagulant. You should tell them well before your appointment.
Warfarin: You would usually stop taking warfarin about 3 days before planned surgery, depending on the type of surgery, and start taking it again straight away afterwards. You would not usually need to stop taking warfarin before dental surgery, but your blood clotting would be tested to help decide. Ask your dentist for advice.
Dabigatran: You would usually stop taking dabigatran for 12 to 48 hours before planned surgery or dental treatment, and start taking it again soon after the surgery, but check with your doctor or dentist first.
Rivaroxaban: You would usually stop taking rivaroxaban for 24 to 48 hours before planned surgery or dental treatment, and usually start taking it again soon after the surgery, but check with your doctor or dentist first.
What happens if the effects of the medicine need to be reversed in an emergency (for example, after an injury or before emergency surgery)?
If you have a serious injury or need urgent surgery, you are more likely to have major bleeding because you take an anticoagulant.
Warfarin: A reversal agent is available.
Dabigatran: A reversal agent is available.
Rivaroxaban: There is currently no reversal agent for rivaroxaban available in New Zealand.
To find out more about the risks and benefits of these medicines, talk with your GP or specialist.