For many people with atrial fibrillation, blood thinners are a good choice to help prevent strokes.
But blood thinners can also cause bleeding, so these medicines aren’t right for everyone.
This guide will help you decide together with your doctor or a member of your care team if blood thinners are right for you.
Before you go on, make sure this guide is right for you. It was created for people who have been told by a doctor that they have atrial fibrillation.
This guide is not right for you if any of the following situations is true:
If any of those is true for you, or if you’re not sure, don’t use this guide. Talk to your doctor about the best options for your situation.
For some people, the personalized estimates in this guide may be less accurate. That’s the case if either of the following situations is true:
If either of those is true for you, most of the information in this guide will still be useful. But it’s important to discuss the decision with your doctor afterwards to make sure you have the most accurate information for your situation.
If you're not sure if this guide is right for you, check with your doctor.
Atrial fibrillation is an irregular heart rhythm in the top part of your heart (the atria).
Most people with atrial fibrillation, even people who don’t feel any symptoms, have a higher risk of stroke than people without atrial fibrillation.
Learn More: How can atrial fibrillation cause a stroke?
The top two parts of your heart are called the atria (the plural of atrium).
Strokes can cause sudden numbness or weakness of the face, arm, or leg, especially on one side of the body. Strokes can also cause sudden confusion, trouble speaking or understanding, or even trouble seeing in one or both eyes. Some people recover from these symptoms. For other people, these symptoms become permanent and lead to trouble thinking, walking, eating, or talking. The problems may make it hard for people to live alone and take care of themselves. Strokes can even cause death.
Because atrial fibrillation can cause a stroke, your doctor may talk to you about taking a blood thinner to reduce the chance of stroke.
If you have atrial fibrillation, you should know the warning signs of a stroke and seek emergency care if you notice them.
Learn More: What are the warning signs of a stroke?
For most people with atrial fibrillation, blood thinners lower the risk of stroke. They work by helping to prevent a blood clotA clump of blood cells. Clots are helpful to stop bleeding after you cut yourself. But atrial fibrillation can create clots inside the heart that travel to an artery of the brain, which can cause a temporary stroke or a stroke. from forming.
The two main types of blood thinners are:
Anticoagulants for people with atrial fibrillation are:
Another option is to take no blood thinner. It's your choice. That's the point of this Smart Decision Guide.
Note that some people can't take one or more of these medicines because of other health problems they have.
This guide focuses on blood thinners only. In addition to prescribing blood thinners, your doctor may treat your atrial fibrillation with other medicines or procedures.
Learn More: Are there treatments besides taking medicines?
Now let’s learn about your personal risk of stroke. This guide includes a risk calculator to help you make a better decision with your doctor about blood thinners.
On the following pages you’ll:
Learn More: Where did these questions come from?
Once you have answered all the questions, click ‘next’ to see your results.
You must answer all of the questions on the page before moving forward.
Based on your age, sex, and medical history, doctors say you have a low risk of stroke.
Your risk of stroke in the next 5 years is less than 1%. That means if 100 people with the same risk level don't take any blood thinner, fewer than one of them would be expected to have a stroke in the next 5 years.
Based on your low risk of stroke, experts recommend choosing one of these two options:
Experts recommend that many people who have a low risk of stroke not take a blood thinner. That’s because experts believe the possible harms from blood thinners outweigh the possible benefits if you have a low risk of stroke.
But your doctor may have a reason to recommend a blood thinner. So it’s important to talk to your doctor about what is best for you.
On the next page, you will see the questions and your answers. You can print the page to share with your doctor and talk about what’s right for you.
You said “I’m not sure” to one or more of the questions. Without knowing these answers, this guide can’t estimate your risk of stroke. That also means this guide can’t tell you which blood thinners (if any) might be right for you.
Talk with your doctor and find out the answers to the questions. Then you can go back and select the right answers.
On the next page, you will see the questions and your answers. You can print the page to share with your doctor and talk about the questions you’re unsure about.
Once you have all the answers, please come back to this Smart Decision Guide and answer the questions again.
Based on your age, sex, and medical history, doctors say you don't have a high risk of stroke.
In general, experts recommend you choose one of these two options:
Based on research that studied people who don't have a high risk of stroke, the evidence is unclear how much blood thinners can help. So it's hard for this Smart Decision Guide to give you more information.
Your best move is to talk with your doctor about your situation and your options. Then together you can decide which course of action is right for you.
On the next page, you will see the questions and your answers. You can print the page to share with your doctor and talk about what’s right for you.
Based on your age, sex, and medical history, doctors say you have a high risk of stroke.
For most people with a high risk of stroke, doctors recommend that you take an anticoagulant.
But some people may decide with their doctors that not taking an anticoagulant is the best option for them. For example, this may be the case if your risk of bleeding is high. Then you and your doctor may make a different decision.
Learn More: Tell me more about my options.
On the next page, you can see how much an anticoagulant would reduce your risk of stroke.
These estimates are averages for people with a similar age, sex, and medical history as you have. These estimates are to help you get ready to talk with your own doctor, who knows more about your personal situation.
You said “I’m not sure” to one or more of the questions. That means that your risk of stroke might be higher than the numbers below.
At the end of this guide you can print a list of the questions to share with your doctor and find out all the answers. Then you can go back to this guide and select the right answers, which will give you good estimates of your risk.
You have a 49% risk of stroke in the next 5 years.
If 100 people with your risk of stroke don’t take an anticoagulant, 49 will have a stroke in the next 5 years. The other 51 people won't have a stroke.
Note: This estimate is from research with people who don’t take any blood thinner, even aspirin.
You have a 18% risk of stroke in the next 5 years.
If 100 people with your risk of stroke take an anticoagulant, 18 will have a stroke in the next 5 years. The other 82 people won't have a stroke.
Note: This estimate is from research with people who take warfarin.
Learn More: What if you took another anticoagulant instead of warfarin?
Each of the 100 circles represents one person who has the same risk of stroke as you do.
Learn More: Where did these numbers come from?
Here are the upsides and downsides of not taking an anticoagulant.
Click any of the 
signs below to learn more about that topic.
Some people who are concerned about bleeding may decide to not take an anticoagulant. Anticoagulants increase the risk of bleeding as a side effectA problem or harm caused by taking a medicine..
For some people the risk of serious bleeding is higher than the risk of stroke. These people may decide with their doctors that the benefit of taking an anticoagulant (preventing stroke) isn't worth the risk of bleeding.
Other medicines that you may take for other health problems also increase the risk of bleeding. Certain health problems, such as serious bleeding in the past, also increase the risk of bleeding.
Learn More: What other medicines increase the risk of bleeding?
You and your doctor can review your medicines and health history to find out your risk of bleeding. That may change your decision about whether to take an anticoagulant.
If you don’t take an anticoagulant, your risk of stroke will be higher. Anticoagulants reduce the risk of stroke more than other blood thinners can.
That’s why doctors usually recommend anticoagulants for people who have a high risk of stroke.
If you don’t take an anticoagulant, there are no extra pills to remember to take and no changes to your daily life. People who take anticoagulants take a pill once or twice a day.
People who take anticoagulants should avoid activities that could cause serious injury and bleeding. Your doctor can tell you whether you'd need to change any activities if you took an anticoagulant.
Certain anticoagulants may also require you to change your daily life in other ways. For example people who take warfarin need to get blood tests at least every month and keep track of the dark-green vegetableslike spinach, broccoli, lettuce, or cabbage they eat.
If you don’t take an anticoagulant, you don’t need to do these things.
Here are the upsides and downsides of taking an anticoagulant.
Click any of the signs below to learn more about that topic.
Anticoagulants lower your risk of stroke. Because you have a high risk of stroke, doctors recommend that most people with high risk consider taking an anticoagulant. That’s because anticoagulants lower your risk of stroke more than other blood thinners can.
Anticoagulants can cause bleeding, or worsen bleeding from another health problem. Usually the bleeding is minor, but sometimes it can be serious.
Other medicines that you may take for other health problems also increase the risk of bleeding. Certain health problems, such as serious bleeding in the past, also increase the risk of bleeding.
Learn More: What other medicines increase the risk of bleeding?
You and your doctor can review your medicines and health history to find out your risk of bleeding. That may change your decision about taking an anticoagulant.
Anticoagulants can also cause other side effects. It depends on the medicine, but some examples include stomach pain and skin bruising.
Learn More: What are the other possible side effects of blood thinners?
Anticoagulants are taken daily. They are taken once or twice a day:
An anticoagulant only works if you take it as often as your doctor prescribes. Missing doses increases your risk of stroke.
Warfarin requires blood tests at least every month. Other anticoagulants don't require blood tests as often. Most people who take warfarin go to a clinic, lab, or doctor’s office to have a blood test taken from their arm or finger. Some people may have the option to have blood tests at home.
Sometimes the results of the blood tests lead the doctor to change the dose of warfarin you take.
If you take any anticoagulant, whether it's warfarin or another anticoagulant, you may need other blood tests. For example you might get tests to check on your kidneys while you take the drugs. These tests are not done as often as the regular blood tests that also come with taking warfarin.
Anticoagulants may require some changes in your daily life. People who take an anticoagulant should avoid activities that could cause serious injury and bleeding.
If you take warfarin, you also should keep track of the dark-green vegetables like spinach, broccoli, lettuce, or cabbageyou eat. These vegetables are high in vitamin K, so eating them affects how warfarin works. If you do eat these vegetables, you’ll want to eat the same amount of them the same number of times each week. That way your warfarin will work consistently to help prevent strokes.
You can buy generic versions of warfarin. The other anticoagulants aren't available as generics. Generic versions of a medicine usually cost less than brand names. You can only buy brand name versions of the other anticoagulants (apixaban, dabigatran, and rivaroxaban). Generic versions of these medicines are not available.
People who take warfarin may also have costs for getting blood tests.
What you yourself might have to pay depends on your health insurance.
In addition to your risk of stroke, and how much an anticoagulant would lower this risk, you and your doctor will also want to think about your risk of bleeding.
People may have bleeding problems even if they don’t take an anticoagulant. But taking an anticoagulant increases your risk of bleeding. This includes:
If you have a bleeding problem or need surgery right away, your doctor may need to quickly reverse the effects of an anticoagulant.
While this guide can estimate your risk of stroke, only your doctor can estimate your risk of serious bleeding.
To help you get ready to talk with your doctor, these estimates are averages for people with atrial fibrillation. On the next page you can read about some things that can make your risk of bleeding higher.
You have a 3% risk of serious bleeding in the next 5 years.
If 100 people don’t take an anticoagulant, 3 will have serious bleeding in the next 5 years. The other 97 people won’t have serious bleeding.
Note: This estimate is from research with people who don’t take any blood thinner, even aspirin.
You have a 7% risk of serious bleeding in the next 5 years.
If 100 people take an anticoagulant, 7 will have serious bleeding in the next 5 years. The other 93 people won’t have serious bleeding.
Note: This estimate is from research with people who take warfarin.
Learn More: What if you took another anticoagulant instead of warfarin?
Each of the 100 circles represents one person.
As you decide whether a blood thinner is right for you, it's important to also consider whether you're at higher risk of bleeding.
The following list describes other things that will increase your risk of bleeding. The more of these that apply to you, the higher your risk of bleeding may be:
This list will be on the summary page you can print to discuss with your doctor.
People consider many things when deciding about whether or not to take an anticoagulant. Before you make a decision, think about what’s important to you. On the next page, you’ll be able to see how well your options (not taking an anticoagulant or taking an anticoagulant) match what you want.
Doctors think stroke and bleeding matter most. But other factors can affect how easy or hard it will be for you to take an anticoagulant. If these other factors matter to you, talk to your doctor so you can make the best choice for you.
Click 
to learn more.
Strokes can cause serious health problems that can make it hard for you to live alone. Strokes can cause death. Bleeding can be minor or it can be serious, such as bleeding in your stomach or brain, from a serious injury, or bleeding that won’t stop. Blood thinners have to be taken every day. Missing doses increases your risk of stroke. Warfarin requires regular blood tests at least every month. Other anticoagulants don’t require blood tests as often. Warfarin is available as a generic. Other anticoagulants aren’t, and will cost more. This table compares your two options based on what’s important to you. Use this information to help you think about which option seems best to you at this point.
While most doctors feel that stroke and serious bleeding are the most important factors in this decision, you may have other concerns related to your daily life.
Strokes can cause serious health problems that can make it hard for you to live alone. Strokes can cause death.
You have a higher risk of stroke if you don't take an anticoagulant. How much higher depends on your personal risk.
Bleeding can be minor or it can be serious, such as bleeding in your stomach or brain, from a serious injury, or bleeding that won’t stop.
You have a higher risk of serious bleeding if you take an anticoagulant. How much higher your personal risk is depends on the other medicines you take and your other health problems.
Talk to your doctor about your personal risk of bleeding.
Blood thinners have to be taken every day. Missing doses increases your risk of stroke.
Warfarin requires regular blood tests at least every month. Other anticoagulants don’t require blood tests as often.
If you take warfarin, you need blood tests at least every month.
If you take another anticoagulant, you may need blood tests but not as often.
If the need for blood tests matters to you, talk to your doctor about it.
Warfarin is available as a generic. Other anticoagulants aren’t, and will cost more. You can buy generic warfarin.
Other anticoagulants are only available as brand names.
If the cost of anticoagulants matters to you, tell your doctor.
Talk to your doctor about why not taking an anticoagulant seems right to you. There might be information your doctor can share that will be important as you decide.
It can be hard to remember all the questions you want to ask your doctor. Here you can make a list of questions.
On the next page you will be able to print out this list of questions to bring with you to your doctor.
it.
it.
when you’re done.
Up/DownUp/DownUp/DownUp/DownUp/DownUp/DownUp/DownTalk to your doctor about why taking an anticoagulant seems right for you, and find out what else you should think about as you decide.
It can be hard to remember all the questions you want to ask your doctor. Here you can make a list of questions.
On the next page you will be able to print out this list of questions to bring with you to your doctor.
it. it. when you’re done.Up/DownUp/DownUp/DownUp/DownUp/DownUp/DownUp/DownUp/DownUp/DownUp/DownUp/DownUp/DownUp/DownTalk to your doctor about which option is best for you. There might be information your doctor can share that will help you decide.
It can be hard to remember all the questions you want to ask your doctor. Here you can make a list of questions.
On the next page you will be able to print out this list of questions to bring with you to your doctor.
it. it. when you’re done.Up/DownUp/DownUp/DownUp/DownUp/DownUp/DownThis summary will help you decide together with your doctor or a member of your care team if blood thinners are a good option for you.
For many people with atrial fibrillation, blood thinners are a good option to help prevent strokes. But blood thinners can also cause bleeding, which sometimes can be serious. So these medicines aren't right for everyone.
Because you answered “I’m not sure” to some of the questions, it's not possible to accurately estimate your risk of stroke. It's important to talk with your doctor to be sure you have the right answers to these questions.
Most people with atrial fibrillation have an increased risk of stroke. So for many people with atrial fibrillation, blood thinners are a good option to help prevent strokes. But blood thinners can also cause bleeding, which sometimes can be serious. So these medicines aren’t right for everyone.
Note that the information that follows is based on your answers to the questions above. Please review your answers with your doctor to be sure the answers are right.
Your doctor may want to know that, based on your answers, your CHA2DS2-VASc score is . Doctors use this score to estimate a person’s risk of stroke. A score of 0 is the lowest risk and 9 is the highest risk.
You said “I’m not sure” to one or more of the questions above. That means that your risk of stroke might be higher than the numbers below.
Talk with your doctor to find out all the answers to these questions. Then you can go back to the risk calculator and select the right answers, which will give you good estimates of your risk.
You have a 49% risk of stroke in the next 5 years.
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If 100 people with your risk of stroke don’t take an anticoagulant, 49 will have a stroke in the next 5 years. The other 51 people won't have a stroke.
Note: This estimate is from research with people who don’t take any blood thinner, even aspirin.
You have a 18% risk of stroke in the next 5 years.
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If 100 people with your risk of stroke take an anticoagulant, 18 will have a stroke in the next 5 years. The other 82 people won't have a stroke.
Note: This estimate is from research with people who take warfarin.
Each of the 100 circles represents one person who has the same risk of stroke as you do.
Some people with atrial fibrillation have a low risk of stroke. Based on your answers, this seems to be true for you.
But it’s important to talk with your doctor to be sure you have the right answers. Then together you can decide whether or not a blood thinner is right for you.
Some people with atrial fibrillation don't have high risk of stroke. Based on your answers, this seems to be true for you.
But it’s important to talk with your doctor to be sure you have the right answers. Then together you can decide whether or not a blood thinner is right for you.
Depending on your risk of stroke, you and your doctor may consider:
If you and your doctor are considering whether you should take a blood thinner, you will also want to consider your risk of bleeding. The list below may be helpful as you talk.
Talk with your doctor about whether any of these things apply to you. The more that do, the higher your risk of bleeding may be. That might affect your decision.
This information is based on the following scientific articles:
Pisters R, et al. (2010). A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest, 138(5):1093-1100.
Estimates for risk of stroke are based on a risk calculator developed for this Smart Decision Guide. It estimates the risks of stroke over 5 years for people who don't take a blood thinner and people who take warfarin.
