Warfarin — Drug Interactions, Alcohol & Pregnancy Guide
Last reviewed: · Source: US FDA drug label database · 247CanITakeWith Editorial Team
- Warfarin is a Anticoagulant (vitamin K antagonist) used for DVT prevention and treatment.
- Alcohol: Use caution — even moderate alcohol can unpredictably alter how warfarin works, making your blood either too thin or not thin enough.
- Pregnancy: Warfarin is contraindicated in pregnancy — it causes fetal warfarin syndrome and bleeding. Heparin is the safe anticoagulant in pregnancy.
- This page covers 4 specific drug combinations with Warfarin.
About Warfarin
Warfarin is an anticoagulant (blood thinner) that prevents blood clots. It requires regular INR blood tests as many foods, drugs, and illness can affect its level. It is being increasingly replaced by NOACs (e.g. apixaban, rivaroxaban) but remains widely prescribed.
Also sold as: Coumadin, Marevan
Warfarin at a glance
Warfarin is classed as anticoagulant (vitamin k antagonist) and is used for dvt prevention and treatment, pulmonary embolism, atrial fibrillation (stroke prevention), mechanical heart valves. It is a prescription medicine, so doses and combinations should always be agreed with your prescriber or pharmacist.
Typical adult dosing guidance: Individualised based on INR target; typically 2-10mg daily. Your own label or prescription always takes priority over general figures.
Interactions most often flagged
- Aspirin
- Ibuprofen
- Alcohol
- Pregnancy
- Paracetamol
Before you combine Warfarin with anything new
- Read the patient information leaflet for both products.
- Keep one up-to-date list of every medicine and supplement you take.
- Ask a pharmacist — it is free and takes a couple of minutes.
- Seek urgent medical help if you feel seriously unwell after combining medicines.
Warfarin and Alcohol
Use caution — even moderate alcohol can unpredictably alter how warfarin works, making your blood either too thin or not thin enough.
Full guide →Warfarin in Pregnancy
Warfarin is contraindicated in pregnancy — it causes fetal warfarin syndrome and bleeding. Heparin is the safe anticoagulant in pregnancy.
Full guide →Warfarin — Drug Combinations
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Frequently Asked Questions
What is Warfarin used for?
Warfarin is a Anticoagulant (vitamin K antagonist) used for DVT prevention and treatment, Pulmonary embolism, Atrial fibrillation (stroke prevention), Mechanical heart valves.
What is the maximum adult dose of Warfarin?
The maximum adult dose is Individualised based on INR target; typically 2-10mg daily. This is general guidance — always follow the dose on your prescription or product label, and check with a pharmacist if you're unsure.
Can I drink alcohol with Warfarin?
Use caution — even moderate alcohol can unpredictably alter how warfarin works, making your blood either too thin or not thin enough.
Is Warfarin safe to take during pregnancy?
Warfarin is contraindicated in pregnancy — it causes fetal warfarin syndrome and bleeding. Heparin is the safe anticoagulant in pregnancy.
Is Warfarin available over the counter in the UK?
Warfarin is prescription-only in the UK.
What should I check before taking Warfarin with other medicines?
The interactions most often flagged for Warfarin are: aspirin, ibuprofen, alcohol, pregnancy, paracetamol. Tell your pharmacist or prescriber about everything you take, including over-the-counter products, supplements and herbal remedies, before combining it with anything new.
What are the brand names for Warfarin?
Warfarin is sold under brand names including Coumadin, Marevan. The active ingredient is the same, so check labels carefully to avoid doubling up on it.
Do I need a prescription for Warfarin?
Warfarin is a prescription medicine, so take it exactly as your prescriber directed and ask them before changing the dose.
Not sure if Warfarin is safe with your other medications?
HealthLabs.com lets you check liver enzyme or kidney function levels before combining medications long-term — no GP referral needed.
Check your levels at HealthLabs →Always speak to your pharmacist or GP for personalised medical advice. Affiliate link — we may earn a commission.