Anticoagulants: The Quick Reference
Anticoagulants: the whole thing in five minutes, for when you want the numbers and nothing else.
Blood thinners: medicines that reduce the blood's ability to clot, used to prevent and treat clots.
Key takeaways
- Types: warfarin, and direct oral anticoagulants such as apixaban and rivaroxaban
- Warfarin: needs regular INR blood tests; direct oral anticoagulants generally do not
- Most useful single change: Carry a card or wear a medical alert ID saying you take a blood thinner.
- Commonest mistake: NSAIDs such as ibuprofen, naproxen or aspirin without your doctor's advice.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
The numbers, in one place
| Measure | Figure |
|---|---|
| Types | warfarin, and direct oral anticoagulants such as apixaban and rivaroxaban |
| Warfarin | needs regular INR blood tests; direct oral anticoagulants generally do not |
| Warfarin and vitamin K | keep leafy green intake consistent, not absent |
| NSAIDs | increase bleeding risk substantially |
| Medical ID | carry a wallet card or wear an alert ID at all times |
In one paragraph
They substantially reduce stroke and clot risk, and the bleeding risk they carry needs specific practical management.
Worth doing
- Carry a card or wear a medical alert ID saying you take a blood thinner
- Tell every dentist, pharmacist and clinician before any procedure
- Keep vitamin K intake consistent if you take warfarin
- Ask your doctor or pharmacist before using any pain reliever; acetaminophen (Tylenol) is often preferred over NSAIDs
Worth avoiding
- NSAIDs such as ibuprofen, naproxen or aspirin without your doctor's advice
- Missing doses, particularly with direct oral anticoagulants
- Starting new medicines or supplements without checking interactions
Related topics
- Atrial Fibrillation: What the Evidence Actually Says (Heart Health)
- Stroke: What Published Guidance Supports (Brain Health)
- What the Guidance Really Says About Suspected Stroke (Emergency Care)
- The Evidence on Hormonal Contraception and Health, Without the Hype (Thyroid and Hormones)
Where to go next
- A Working Checklist for Anticoagulants
- What People Get Wrong About Anticoagulants
- Anticoagulants — the reference entry
- Blood Health: The Complete Guide
- Blood Donation: Sorting the Evidence From the Noise
- What the Guidance Really Says About Sickle Cell and Thalassemia
When to speak to a doctor
Get medical care the same day after any head injury while taking a blood thinner, even if you feel well and there is no visible injury. Call 911 for vomiting blood, black tarry stools, a severe headache, sudden weakness on one side, or bleeding that will not stop after 10 minutes of firm pressure. Contact your doctor about unusual bruising, pink or brown urine, or nosebleeds that keep coming back.
Where this comes from
- MedlinePlus — Blood Thinners
- National Heart, Lung, and Blood Institute — Venous Thromboembolism
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.
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