Safe use of blood thinners (anticoagulants)
Content date: 10 November 2026
Anticoagulants help prevent clots forming or growing, but can increase bleeding. Instructions differ between medicines and between regimens for the same medicine. Follow your written plan. This guide supports safe use; it does not select treatment or replace follow-up.
Your next step
Carry a card showing your medicine, reason and dose. Arrange tests before the prescription runs out. Print the plan below for your team to complete.
Get urgent help: Vomiting blood, black stools, uncontrolled bleeding, fainting, sudden severe headache or new weakness: go to emergency care immediately. A head injury needs urgent assessment even if you feel well. Do not wait for a message reply. Bring the medicine name and last-dose time.
Are all blood thinners the same?
- Anticoagulants include warfarin, direct oral medicines such as apixaban, rivaroxaban, dabigatran and edoxaban, and injections such as enoxaparin. Aspirin and clopidogrel act on platelets and cannot replace an anticoagulant. A doctor may prescribe a combination for a specific reason. Do not switch or combine them yourself.
How do I take it?
- Follow the prescribed dose and times; do not stop because symptoms improve. Food instructions vary: rivaroxaban 15 mg and 20 mg tablets must be taken with food. These strengths illustrate administration, not a dose recommendation. Ask the pharmacist about your specific product.
- For enoxaparin injections, receive practical training before injecting under the skin at home. Rotate sites as instructed, avoid rubbing afterwards, and place used needles in a sharps container away from children.
What if I miss a dose?
- Request written instructions for your medicine, dose and frequency: there is no single rule for all anticoagulants. Contact the pharmacist or treating team promptly after a missed or extra dose, or vomiting after a dose. Do not guess how to compensate or follow another medicine's instructions.
What monitoring is needed?
- Warfarin needs INR blood tests to guide dosing by measuring how quickly blood clots. Direct oral anticoagulants are not usually adjusted using INR, but still need reviews, blood counts, and kidney and liver tests. Your team sets the schedule; illness, medicine changes or kidney problems may require closer monitoring.
Medicines, food and storage
- Check new medicines, including antibiotics, herbs and supplements, with your pharmacist. Do not add ibuprofen, diclofenac or aspirin yourself: bleeding may increase. If aspirin or clopidogrel is already prescribed, do not stop it without an agreed plan.
- With warfarin, keep vitamin K-rich vegetables reasonably consistent rather than avoiding them. Follow pack storage instructions; protect medicines from heat, moisture and children. Dabigatran capsules need their original packaging for moisture protection; ask before transferring them into a pill organiser.
Liver disease, kidneys, pregnancy and breastfeeding
- Tell your team about cirrhosis or kidney impairment: not every anticoagulant suits every disease stage, and the medicine or dose may need changing. Seek early advice when planning pregnancy, becoming pregnant or breastfeeding. Do not stop or substitute treatment yourself; stopping may restore the risk of clotting.
Before endoscopy or dental treatment
- Inform the prescriber and gastroenterologist or dentist early. Decisions depend on clotting and bleeding risk, the procedure and kidney function. Diagnostic endoscopy with simple biopsies is usually lower risk than removing polyps; anticipated treatment during endoscopy may change the plan.
- There is no universal stopping interval. Get the last dose and restart time in writing, or confirmation to continue when appropriate. Temporary replacement with injections is not needed for everyone and must not be arranged yourself. Bring your medication card and mention coronary stents, mechanical heart valves or recent clots.
Your plan: complete with the treating team
Print, complete by hand, and keep with your medicines list.
Medicine and reason: ____________________
Dose, times and food: ____________________
Missed-dose instructions: ____________________
Tests and follow-up: ____________________
Procedure and date: ____________________
Continue or last dose before procedure: ____________________
Restart time and team approving plan: ____________________
Team or pharmacy telephone: ____________________
© 2026 Dr. Ibrahim Albedaiwi — Patient guide
When to get help
Vomiting blood, black stools, uncontrolled bleeding, fainting, sudden severe headache or new weakness: go to emergency care immediately. A head injury needs urgent assessment even if you feel well. Do not wait for a message reply. Bring the medicine name and last-dose time.
Contact the team promptly for new large bruises, repeated minor bleeding, heavier periods, or an extra or missed dose. Heavy bleeding or bleeding with dizziness requires emergency care.