Cranberry Juice and Warfarin: When Bad Publicity Trumps Science

Abstract Based on anecdotal reports, the question of whether cranberry juice interacts with warfarin has been raised. This article discusses the potential mechanism, and systematically reviews case reports as well as clinical trials examining the possible interaction. We systematically searched MEDL...

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Bibliographic Details
Published inThe American journal of medicine Vol. 123; no. 5; pp. 384 - 392
Main Authors Zikria, Jennifer, MD, Goldman, Raimonda, MD, Ansell, Jack, MD
Format Journal Article
LanguageEnglish
Published New York, NY Elsevier Inc 01.05.2010
Elsevier
Elsevier Sequoia S.A
Subjects
Aged
Anticoagulant therapy
Anticoagulants - pharmacology
Anticoagulation
Biological and medical sciences
Clinical trials
Cranberry juice
Drug Interactions
Female
Fruit juices
General aspects
Humans
Internal Medicine
Male
Medical sciences
Middle Aged
Pharmacology
Systematic review
Thrombolytic drugs
Vaccinium macrocarpon
Warfarin
Warfarin - pharmacology
Cranberry juice
Warfarin
Anticoagulation
Drug interactions
Anticoagulant therapy
Medicine
Antivitamin K
Anticoagulant
Sciences
Coumarine derivatives
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Summary:Abstract Based on anecdotal reports, the question of whether cranberry juice interacts with warfarin has been raised. This article discusses the potential mechanism, and systematically reviews case reports as well as clinical trials examining the possible interaction. We systematically searched MEDLINE via PubMed, and the Cochrane Library database. Fifteen case reports were summarized, including the initial unpublished brief reports to the Committee on Safety of Medicines and the subsequent 6 published case reports. Seven clinical trials were analyzed, including 3 studies using warfarin and 4 surrogate drugs. Only 2 cases had a validation scale suggesting a “probable” interaction, but even in these patients there were many reasons to question the validity of a relevant drug interaction. Randomized clinical trials and surrogate markers found no evidence to support the interaction between cranberry juice and warfarin. Because the moderate consumption of cranberry juice does not affect anticoagulation, we encourage the reexamination of initial warnings based on scientific evidence. We conclude that the initial precautionary warnings by administrating bodies are limited to anecdotal case reports and represent misleading conclusions.
ISSN:0002-9343
1555-7162
DOI:10.1016/j.amjmed.2009.08.019