Cranberry and Warfarin Interaction: A Case Report and Review of the Literature

Abstract

This case reports on a patient whose International Normalized Ratio (INR) increased after ingestion of cranberry sauce while stabilized on warfarin. It is followed by a review of the published literature on the potential interaction between the two.An 85-year-old woman on chronic warfarin therapy for atrial fibrillation experienced INR elevations of two- to three-fold after two separate ingestions of cranberry sauce. In each case, her INR values decreased after withholding three to four doses and resuming a similar maintenance dose of warfarin. Although the majority of the pharmacokinetic and pharmacodynamic studies did not find a significant interaction between cranberry and warfarin, several case reports indicate that cranberry products may increase INR values in patients on warfarin. Practitioners should consider cranberry usage as a potential contributor in the evaluation of supratherapeutic INR values in patients on warfarin.

Nutraceutical-based Integrative Medicine: Adopting a Mediterranean Diet Pyramid for Attaining Healthy Ageing in Veterans with Disabilities

“…Therefore, the presence of glucosinolates, flavonoids and furanocoumarins in some plant foods and beverages must be taken into consideration owing to their potential interfering with drugs metabolism and bioavailability, despite the positive association between cognitive function and consumption of cruciferous vegetables and citrus fruits [149]. Interactions between drugs and natural fruit juices have been reported, especially grapefruit juice [154,155] but also cranberry [156] and pomegranate [157] juices, a quercetin containing muscadine grape [158] and soy protein [159]. Accordingly, considering the high content of bioactive compounds and phytochemicals in plant foods [160], a personalized nutrition (Figure 1) should take into account potential food-drug interactions in veterans who are in treatment for comorbidities.…”

“…As previously suggested, seasonality implies the ''intermittent'' consumption of different foods, which contain a variable mix of bioactive molecules, and it allows to prevent the onset of phenomena of tolerance that might otherwise occur with the chronic intake of a single flavonoid or with a same food source of flavonoids. Although variability could also ensure the maintenance of the single dose of flavonoid below that at which adverse effects in some individuals genetically predisposed or unpleasant drug interactions in diseased subjects may occur [219], probably the avoidance of foods and beverages with high content of phytochemicals [117,149,[153][154][155][156][157][158][159] could be recommended in subjects under polypharmacy regimes. In these patients, plant foods should be chosen within those containing low phytochemicals and high micronutrients.…”

Herbal Therapy in Pregnancy-What to Expect when you Expect?

“…However, women should not be encouraged to use it as a substitute for antibiotic therapy. Pregnant women on anticoagulant therapy should not be recommended cranberry since cranberry change INR and its interaction with warfarin is well known and documented [57,58]. Women with nephrolithiasis may be at increased risk of stone formation if they consume a large amounts of cranberries [59].…”

Medicines For Women

“…Since then there have been many published reports from different countries and speculation as to the potential interaction and its possible mechanism (Aston et al 2006;Griffiths et al 2008;Haber et al 2012;Hamann et al 2011;Niklasson and Andrén 2006;Rindone and Murphy 2006;Srinivas 2013). The adverse reactions caused by this interaction range from minor bleeding to fatal haemopericardium and gastrointestinal hemorrhage (Griffiths et al 2008).…”