Anticoagulants: What They Do, Medicines
Anticoagulants, often called blood thinners, are prescription medicines that make the blood slower to clot. They are used to treat and prevent harmful blood clots and to lower the risk of stroke in some people. Common examples are warfarin and rivaroxaban. Bleeding is the main risk, and they should never be stopped without a doctor's advice.
Pharmacist review in progress. This page is based on the sources listed below and is being checked by our registered pharmacist.
How do Anticoagulants work?
Anticoagulants block steps in the chain of clotting proteins in the blood, so clots form and grow more slowly. They do not actually thin the blood, and they do not dissolve a clot that has already formed.
Active ingredients of this type
These active ingredients belong to Anticoagulants. They are listed A to Z.
- Rivaroxaban: Rivaroxaban is a prescription blood thinner (anticoagulant) used to treat and prevent harmful blood clots.
- Warfarin: Warfarin is a prescription blood thinner (anticoagulant) used to treat and prevent harmful blood clots.
Common questions
Do blood thinners really thin the blood?
No. They make the blood slower to clot, so new clots are less likely to form or grow. They do not dissolve an existing clot; the body breaks it down over time.
Is it safe to stop a blood thinner when I feel well?
No. Stopping can raise the risk of a clot or stroke. Talk to your doctor, who decides whether any change is suitable and how to stop safely.
What should I do after a fall or head injury?
Get medical help straight away, even if you feel well, because bleeding inside the head can be slow to show. Tell staff that you take a blood thinner, and carry an alert card or note.
Sources
- Warfarin: an anticoagulant medicine. NHS (UK)
- Rivaroxaban (Xarelto): a medicine to prevent blood clots. NHS (UK)
- Xarelto (rivaroxaban) tablets: prescribing information (Janssen, label revised 3/2026). DailyMed, US National Library of Medicine
- Blood clots and deep vein thrombosis (DVT). NHS (UK)
- ATC/DDD Index: B01A Antithrombotic agents. WHO Collaborating Centre for Drug Statistics Methodology
- National Formulary of India. Indian Pharmacopoeia Commission