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

Bleeding risk

Warfarin increases your risk of serious bleeding. You must seek immediate medical attention if you have a fall, a head injury, or notice signs of internal bleeding such as dark/tarry stools or coughing up blood.

Drug interaction

Taking paracetamol regularly or in high doses while on warfarin can increase your risk of bleeding. Consult your doctor before taking paracetamol for more than a few days.

Liver damage

Never exceed the maximum dose of paracetamol (usually 4g in 24 hours). Taking too much can cause fatal liver damage, and symptoms may not appear for several days. Check all other medicines (such as cold and flu remedies) to ensure they do not also contain paracetamol.

Pregnancy

Warfarin can cause serious harm to an unborn baby. You must use effective contraception while taking it and inform your doctor immediately if you think you are pregnant.

Food and drink warnings

Alcohol

t is best to avoid or strictly limit alcohol when taking paracetamol. Combining alcohol and paracetamol increases the risk of serious liver damage.

It is best to avoid or strictly limit alcohol while taking warfarin. Alcohol can affect how your liver processes the medicine, which may increase your risk of bleeding or cause your INR levels to become unstable. If you do drink, keep it to a minimum and do not binge drink.

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

Vitamin K helps your blood to clot, which works against warfarin. You do not need to avoid these foods entirely, but you must keep the amount you eat consistent. A sudden increase or decrease in vitamin K intake can change how well your warfarin works.

Cranberry juice and Goji berries

Cranberry juice and goji berry products can significantly increase the blood-thinning effect of warfarin, leading to a higher risk of bruising or bleeding. It is best to avoid these while taking warfarin.

Grapefruit juice

Grapefruit juice may increase the levels of warfarin in your blood, which can increase your risk of bleeding. It is best to avoid grapefruit juice.

Pomegranate juice

Some evidence suggests pomegranate juice may interact with warfarin and increase the risk of bleeding. It is best 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.