Can I take Warfarin and Paracetamol together?

Why this happens

Warfarin works by blocking the body's ability to use Vitamin K to clot blood. Paracetamol (specifically a breakdown product of it) can interfere with the same enzymes warfarin targets, which adds to the blood-thinning effect.

What you should do

If you only need a one-off dose of paracetamol, it is generally safe. However, if you need to take paracetamol regularly (for more than 3 or 4 days), you must inform your doctor or anticoagulant clinic. They may need to monitor your INR (blood clotting speed) more frequently and adjust your warfarin dose. Always report any unusual bruising, nosebleeds, or bleeding gums to your healthcare provider.

Important precautions

Pregnancy

Warfarin can cause serious birth defects and must not be taken if you are pregnant or planning to conceive. Use effective contraception while taking it.

Vitamin K intake

Sudden changes in your diet, especially eating more green leafy vegetables (rich in Vitamin K), can make warfarin less effective. Keep your intake of these foods consistent.

Regular paracetamol use

Taking paracetamol regularly for several days can increase the blood-thinning effect of warfarin, raising your risk of bleeding. Occasional single doses are generally safe.

Food and drink warnings

Alcohol

Avoid binge drinking. Small amounts of alcohol (1-2 units a day) are usually fine, but heavy drinking can affect how warfarin works and increase your risk of bleeding.

Foods high in Vitamin K (e.g. spinach, kale, broccoli, Brussels sprouts)

Vitamin K helps your blood clot, which is the opposite of what warfarin does. You do not need to avoid these foods, but you must keep the amount you eat consistent. A sudden increase or decrease in vitamin K intake can change your INR levels.

Cranberry juice and cranberry products

Cranberry juice may increase the effect of warfarin, making you more likely to bleed. It is best to avoid cranberry products while taking this medicine.

Grapefruit juice

Grapefruit juice can interfere with the enzymes that break down warfarin, potentially increasing the risk of bleeding. It is best to avoid it or keep your intake very small and consistent.

Pomegranate juice

Some evidence suggests pomegranate juice may increase the effect of warfarin. It is safer to avoid it.

Using other medicines

Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.