Painkillers, paracetamol - Interactions 

When two or more medicines are taken at the same time, the effects of one of the medicines can be changed by the other.

This is known as a drug-drug interaction. In some cases, it may not be safe to take one medicine with another because of interaction.

Paracetamol may interact with the following medicines:

• busulfan – treats some types of cancer
• carbamazepine – treats a number of conditions, including epilepsy and some types of pain
• colestyramine – treats a number of conditions, including the itchiness that is caused by primary biliary cirrhosis (a type of liver disease)
• coumarins – these are present in oral anticoagulant medicines (medicines to prevent the blood clotting), such as warfarin (see below)
• domperidone – relieves sickness and treats a number of conditions, including indigestion
• metoclopramide – relieves sickness and treats a number of conditions, including indigestion

To check that your medicines are safe to take with paracetamol, you can:

• ask your GP or local pharmacist 
• read the patient information leaflet that comes with your medicine
• check the Medicines information tab at the top of this page

Warfarin

Warfarin is an anticoagulant (blood-thinning) medicine that is used to treat and prevent conditions such as:

• deep vein thrombosis – a blood clot in one of the deep veins of the body
• strokes – where the blood supply to the brain is restricted

If you take warfarin, prolonged regular use of paracetamol may increase its anticoagulant effect, making it more difficult for your blood to clot. This can increase the risk of bleeding. This effect is not thought to happen with occasional doses of paracetamol.

See warfarin for more information.

Paracetamol-containing medicines

Unless otherwise directed by your GP or pharmacist, you should not take paracetamol with other products that contain paracetamol, such as co-dydramol, co-codamol and Tramacet. This is due to the risk of overdosing on paracetamol.