Blood thinners (oral anticoagulants) to prevent stroke in AF

People with atrial fibrillation may be offered a blood thinner to prevent the clots that can cause a stroke. NHLBI names warfarin and the direct-acting oral anticoagulants apixaban, dabigatran, rivaroxaban and edoxaban. Blood thinners can cause bleeding, and MedlinePlus calls bleeding their most common side effect.

Intervention
In this atlas

Overview

Technical summary

Parent page for warfarin and the direct oral anticoagulants (DOACs) used in atrial fibrillation. The three DOAC substances with a page here (apixaban, dabigatran, rivaroxaban) were each compared with warfarin in a large randomized trial: ARISTOTLE, RE-LY and ROCKET AF. Their results are on the substance pages. Edoxaban is named by NHLBI and has no page. Warfarin has no page. The text rests on NHLBI and MedlinePlus patient pages and gives no event rates.

About this intervention

Type: Medicine
Mechanism: Blood thinners stop clots from forming in the blood. They do not break up clots a person already has (MedlinePlus).

Claims and evidence

Context Adults with atrial fibrillation, in general terms (NHLBI and MedlinePlus patient pages)

Recipient: Adult
Population: People with atrial fibrillation, described in general terms. NHLBI puts the number of US adults with atrial fibrillation above 2 million and says the chance of developing it grows with age. The pages do not describe a study population.
Care setting: Not applicable (patient information pages, not a study)
Geography: Not stated in the pages for most statements; the prevalence sentence refers to the United States
Life stage: Adults in general. NHLBI describes atrial fibrillation as uncommon in children.
Follow-up: Not applicable (patient information pages)

Eligibility: inclusion criteria not stated; exclusion criteria not stated

Included: None stated
Excluded: None stated

Description Evidence synthesis Certainty not assessed

NHLBI names warfarin and the direct oral anticoagulants (apixaban, dabigatran, rivaroxaban and edoxaban) as medicines that stop clots from forming and so reduce the chance of stroke. It says a person at risk of stroke may need one, and that all of them carry a bleeding risk. MedlinePlus lists atrial fibrillation among the conditions in which a person may need a blood thinner and calls bleeding the most common side effect of blood thinners. Neither page gives a number.
Applies to Adult
- People with atrial fibrillation, described in general terms. NHLBI puts the number of US adults with atrial fibrillation above 2 million and says the chance of developing it grows with age. The pages do not describe a study population.
- Not applicable (patient information pages, not a study)
- Not stated in the pages for most statements; the prevalence sentence refers to the United States
- Adults in general. NHLBI describes atrial fibrillation as uncommon in children.
Follow-up Not applicable (patient information pages)
Certainty method
Not assessed

Limitations
Patient information pages. They name edoxaban, which has no page in this atlas. The trial results behind apixaban, dabigatran and rivaroxaban are recorded on their own claims, and the pages give no event rates.

Last checked
2026-10-14

Next evidence check due
Not scheduled
Sources and citations (6)
1. Supports Atrial Fibrillation Treatment (NHLBI)
  
  Webpage · National Heart, Lung, and Blood Institute (NIH) · Edition Page as fetched on 2026-10-14, with the line Last updated on November 30, 2022.
  
  Locator
  Page body, Medicines, Blood thinners (fragment 1)
  
  How it applies
  NHLBI: blood thinners and DOACs, first part of the sentence.
  
  Retrieved
  2026-10-14T18:19:49Z
  
  Source effective date
  Not reported
  
  Source state
  Current
  
  Snapshot hash
  4717eb3d282d9c95f17fc4755692af9a8db61d4e8e2283bbb993b25abde06989
  
  Reuse basis
  Page of the NHLBI website, fetched as cf-nhlbi-atrial-fibrillation-treatment.html. Only the hash is kept. The NHLBI terms pages tried returned HTTP 404 (cf-nhlbi-website-policies.html, cf-nhlbi-copyright.html), the NIH web-policies pages returned HTTP 403 (cf-nih-web-policies-notices.html, cf-nih-copyright.html), and the NHLBI privacy and accessibility page (cf-nhlbi-website-privacy-accessibility.html) states no copyright terms. The arrhythmia page also credits a copyrighted animation. The reuse terms are therefore unverified, so public text is cite_only: facts are stated in this atlas's own words.
2. Supports Atrial Fibrillation Treatment (NHLBI)
  
  Webpage · National Heart, Lung, and Blood Institute (NIH) · Edition Page as fetched on 2026-10-14, with the line Last updated on November 30, 2022.
  
  Locator
  Page body, Medicines, Blood thinners (fragment 2)
  
  How it applies
  NHLBI: these medicines stop clots forming and reduce stroke risk.
  
  Retrieved
  2026-10-14T18:19:49Z
  
  Source effective date
  Not reported
  
  Source state
  Current
  
  Snapshot hash
  4717eb3d282d9c95f17fc4755692af9a8db61d4e8e2283bbb993b25abde06989
  
  Reuse basis
  Page of the NHLBI website, fetched as cf-nhlbi-atrial-fibrillation-treatment.html. Only the hash is kept. The NHLBI terms pages tried returned HTTP 404 (cf-nhlbi-website-policies.html, cf-nhlbi-copyright.html), the NIH web-policies pages returned HTTP 403 (cf-nih-web-policies-notices.html, cf-nih-copyright.html), and the NHLBI privacy and accessibility page (cf-nhlbi-website-privacy-accessibility.html) states no copyright terms. The arrhythmia page also credits a copyrighted animation. The reuse terms are therefore unverified, so public text is cite_only: facts are stated in this atlas's own words.
3. Supports Atrial Fibrillation Treatment (NHLBI)
  
  Webpage · National Heart, Lung, and Blood Institute (NIH) · Edition Page as fetched on 2026-10-14, with the line Last updated on November 30, 2022.
  
  Locator
  Page body, Medicines, Blood thinners
  
  How it applies
  NHLBI: who may need them.
  
  Retrieved
  2026-10-14T18:19:49Z
  
  Source effective date
  Not reported
  
  Source state
  Current
  
  Snapshot hash
  4717eb3d282d9c95f17fc4755692af9a8db61d4e8e2283bbb993b25abde06989
  
  Reuse basis
  Page of the NHLBI website, fetched as cf-nhlbi-atrial-fibrillation-treatment.html. Only the hash is kept. The NHLBI terms pages tried returned HTTP 404 (cf-nhlbi-website-policies.html, cf-nhlbi-copyright.html), the NIH web-policies pages returned HTTP 403 (cf-nih-web-policies-notices.html, cf-nih-copyright.html), and the NHLBI privacy and accessibility page (cf-nhlbi-website-privacy-accessibility.html) states no copyright terms. The arrhythmia page also credits a copyrighted animation. The reuse terms are therefore unverified, so public text is cite_only: facts are stated in this atlas's own words.
4. Supports Atrial Fibrillation Treatment (NHLBI)
  
  Webpage · National Heart, Lung, and Blood Institute (NIH) · Edition Page as fetched on 2026-10-14, with the line Last updated on November 30, 2022.
  
  Locator
  Page body, Medicines, Blood thinners (passage 2)
  
  How it applies
  NHLBI: bleeding risk.
  
  Retrieved
  2026-10-14T18:19:49Z
  
  Source effective date
  Not reported
  
  Source state
  Current
  
  Snapshot hash
  4717eb3d282d9c95f17fc4755692af9a8db61d4e8e2283bbb993b25abde06989
  
  Reuse basis
  Page of the NHLBI website, fetched as cf-nhlbi-atrial-fibrillation-treatment.html. Only the hash is kept. The NHLBI terms pages tried returned HTTP 404 (cf-nhlbi-website-policies.html, cf-nhlbi-copyright.html), the NIH web-policies pages returned HTTP 403 (cf-nih-web-policies-notices.html, cf-nih-copyright.html), and the NHLBI privacy and accessibility page (cf-nhlbi-website-privacy-accessibility.html) states no copyright terms. The arrhythmia page also credits a copyrighted animation. The reuse terms are therefore unverified, so public text is cite_only: facts are stated in this atlas's own words.
5. Supports Blood Thinners | Anticoagulants (MedlinePlus)
  
  Webpage · MedlinePlus, National Library of Medicine · Edition Page as fetched on 2026-10-14.
  
  Locator
  Summary, Who needs blood thinners?
  
  How it applies
  MedlinePlus lists atrial fibrillation among conditions that may need a blood thinner.
  
  Retrieved
  2026-10-14T18:19:51Z
  
  Source effective date
  Not reported
  
  Source state
  Current
  
  Snapshot hash
  2b4141ab8f60f42c97c4cc1dc5da568cf7c4073464f1e0fdfe75043f57d8e4c7
  
  Reuse basis
  MedlinePlus health-topic page, fetched as cf-medlineplus-bloodthinners.html. The raw page is committed at research/snapshots/cf-medlineplus-bloodthinners.html; it also carries licensed images, and only the public-domain summary text is quoted. MedlinePlus says summaries on health topic pages are in the public domain and asks users to acknowledge MedlinePlus as the source (the page titled Linking to and Using Content from MedlinePlus, fetched as cf-medlineplus-usingcontent.html, sha256 31267ce9db016893b80c5665312d92ffc8c34ec86916f84708c353936ba52228). Source: MedlinePlus, National Library of Medicine. This atlas quotes only the summary text.
6. Supports Blood Thinners | Anticoagulants (MedlinePlus)
  
  Webpage · MedlinePlus, National Library of Medicine · Edition Page as fetched on 2026-10-14.
  
  Locator
  Summary, What are the side effects of blood thinners?
  
  How it applies
  MedlinePlus: bleeding is the most common side effect.
  
  Retrieved
  2026-10-14T18:19:51Z
  
  Source effective date
  Not reported
  
  Source state
  Current
  
  Snapshot hash
  2b4141ab8f60f42c97c4cc1dc5da568cf7c4073464f1e0fdfe75043f57d8e4c7
  
  Reuse basis
  MedlinePlus health-topic page, fetched as cf-medlineplus-bloodthinners.html. The raw page is committed at research/snapshots/cf-medlineplus-bloodthinners.html; it also carries licensed images, and only the public-domain summary text is quoted. MedlinePlus says summaries on health topic pages are in the public domain and asks users to acknowledge MedlinePlus as the source (the page titled Linking to and Using Content from MedlinePlus, fetched as cf-medlineplus-usingcontent.html, sha256 31267ce9db016893b80c5665312d92ffc8c34ec86916f84708c353936ba52228). Source: MedlinePlus, National Library of Medicine. This atlas quotes only the summary text.

Clinical links

Each link reports what one cited claim says about one population. "Evaluated for" means studied, not shown to work. These links do not show that anything is effective or right for you.

Claim, not a settled fact Blood thinners lower stroke risk in AF and carry a bleeding risk (NHLBI): Atrial fibrillation (AF) (Evaluated for)
Applies to Adult
- People with atrial fibrillation, described in general terms. NHLBI puts the number of US adults with atrial fibrillation above 2 million and says the chance of developing it grows with age. The pages do not describe a study population.
- Not applicable (patient information pages, not a study)
- Not stated in the pages for most statements; the prevalence sentence refers to the United States
- Adults in general. NHLBI describes atrial fibrillation as uncommon in children.
Follow-up Not applicable (patient information pages)
NHLBI names warfarin and the direct oral anticoagulants (apixaban, dabigatran, rivaroxaban and edoxaban) as medicines that stop clots from forming and so reduce the chance of stroke. It says a person at risk of stroke may need one, and that all of them carry a bleeding risk. MedlinePlus lists atrial fibrillation among the conditions in which a person may need a blood thinner and calls bleeding the most common side effect of blood thinners. Neither page gives a number.
Limitations. Patient information pages. They name edoxaban, which has no page in this atlas. The trial results behind apixaban, dabigatran and rivaroxaban are recorded on their own claims, and the pages give no event rates.

Record details

Record id: cardio:oral-anticoagulation
Content hash: 0051867d76489e7444c63a4ab4d0099e3d6e18cb69b8edcab5220cf1ffd83ed9