Cranberry juice not to be drunk alongside warfarin

- Last updated on GMT

Patients taking the blood-thinning drug warfarin should avoid all
cranberry-based products, according to new advice from the UK's
Committee on Safety of Medicines (CSM), after it reviewed evidence
of several interactions.

Cranberry juice has been found in recent research to have benefits on heart health, with a recent trial showing that a cranberry extract reduced stroke outcome. It is therefore increasingly prescribed for patients after a heart attack or heart surgery.

However, the flavonoids in the fruit are known to inhibit cytochrome P450 activity, the enzymes used to break down warfarin. They have previously been found to interact with many other drugs too.

The UK's medicines authority last year warned users of this possible interaction but last month it issued new 'formal' advice for patients taking warfarin.

The safety committee says it has received a total of 12 reports of suspected interactions involving warfarin and cranberry juice.

It added that: "It is not possible to define a safe quantity or brand of cranberry juice, therefore patients taking warfarin should be advised to avoid this drink unless the health benefits are considered to outweigh any risks."

"It is not known whether other cranberry products, such as capsules or concentrates, might also interact with warfarin. Therefore similar caution should be observed with these products,"​ it added.

Product information for warfarin products is in the process of being updated to reflect this new advice.

Related topics: R&D, Juice Drinks

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