Warfarin can interact with many other medicines. The patient information leaflet that comes with a medicine should tell you if it's safe to take with warfarin.

Ask your GP or pharmacist if you're unsure.

When taking warfarin:

  • don't take aspirin , or treatments containing aspirin, unless it's prescribed by a healthcare professional as it could cause bleeding
  • don't take ibuprofen unless it's prescribed by a healthcare professional
  • you can take paracetamol , but don't take more than the recommended dose

Herbal medicines and supplements can also interact with warfarin. You should therefore avoid taking them without first checking with your GP, pharmacist, or staff at your local anticoagulant clinic.

Food and drink

Some food and drink can interfere with the effect of warfarin if consumed in large amounts, including foods that are rich in vitamin K .

Foods containing large amounts ofvitamin K include:

  • green leafy vegetables, such as broccoli and spinach
  • vegetable oils
  • cereal grains

Small amounts of vitamin K can also be found in meat and dairy foods.

When your first dose of warfarin is prescribed, it doesn't matter how much vitamin K you're eating because the dosage will be based on your current blood clotting levels.

However, if you make significant changes to your diet, such as increasing your vitamin K intake or cutting out foodsthatcontain vitamin K, it could interfere with how warfarin works.

Consult the healthcare professional responsible for your care before making any significant changes to your diet while taking warfarin. They'll also be able to give you more information about foods to avoid or limit.


Getting drunk or binge drinking is dangerous while taking warfarin. It may increase the effect of the drug, increasing the risk of bleeding.

The latest guidelines on drinking alcohol state that regularly drinking more than 14 units of alcohol a week (for both men and women) risks damaging your health.

Fourteen units is equivalent to six pints of average-strength beer or 10 small glasses of low-strength wine.

Content supplied by the NHS Website

Medically Reviewed by a doctor on 21 Dec 2018