title: Clinically relevant interaction between warfarin and scuppernongs, a quercetin containing muscadine grape: continued questions surrounding flavonoid-induced warfarin interactions.
abstract: We present a case of clinically relevant and probable interaction between warfarin and scuppernongs in a 73-year-old woman where ingestion of scuppernongs, a variety of quercetin-containing muscadine grapes, over a period of 2 months was associated with elevations in the International Normalised Ratio to supratherapeutic levels. While muscadine grapes and specifically scuppernongs are found primarily in Southeastern USA, the flavonoid in questionand quercetin is found worldwide as a dietary supplement.
authors: UNC Eshelman School of Pharmacy, Chapel Hill, North Carolina, USA.
authors: Christopher J
authors: CJ
authors: Woodward
authors: University of North Carolina Hospitals and Clinics, Chapel Hill, North Carolina, USA.
authors: Zachariah M
authors: ZM
authors: Deyo
authors: Department of Family Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.
authors: Katrina E
authors: KE
authors: Donahue
authors: Lineberger Comprehensive Cancer Center Biostatistics Core, Chapel Hill, North Carolina, USA.
authors: Allison M
authors: AM
authors: Deal
authors: University of North Carolina Hospitals and Clinics, Chapel Hill, North Carolina, USA Department of Family Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.
authors: Emily M
authors: EM
authors: Hawes
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000494:pharmacology; D019587:Dietary Supplements; D004347:Drug Interactions; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D018565:Food-Drug Interactions; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D019934:International Normalized Ratio; D011794:Quercetin / Q000494:pharmacology; D027843:Vitis / Q000737:chemistry*; D014859:Warfarin / Q000494:pharmacology
chemical_list: D000925:Anticoagulants; D005419:Flavonoids; D014859:Warfarin; D011794:Quercetin