Ambulatory Care, Regional Medical Center at Memphis, Memphis, TN, USA.
Ann Pharmacother. 2011 Mar;45(3):e17. doi: 10.1345/aph.1P451. Epub 2011 Mar 1.
To report a case of warfarin-cranberry juice interaction, which resulted in an international normalized ratio (INR) elevation on 2 separate occasions.
A 46-year-old female was receiving a total weekly dose of 56 mg of warfarin. During the 4 months prior to the incident INR, her average INR was 2.0, with a range of 1.6-2.2, while taking the same weekly dose of warfarin. Her INR increased to 4.6 after drinking approximately 1.5 quarts (1420 mL) of cranberry juice cocktail daily for 2 days. Her INR 14 days later without cranberry juice cocktail consumption was 2.3. For the next 3 months, while taking warfarin 56 mg per week, her average INR was 2.1, with a range of 1.4-2.5. At a subsequent visit, after drinking approximately 2 quarts (1893 mL) of cranberry juice cocktail daily for 3-4 days, her INR had increased to 6.5. Her INR after holding warfarin for 3 days was 1.86. Her INR 7 days after resuming the weekly dose of warfarin 56 mg was 3.2. During both of the elevated INR episodes, no other factors were identified that would have resulted in an elevated INR, such as drug, herbal, disease, or other food interactions. An objective causality assessment revealed the interaction was highly probable.
Warfarin is the most commonly used anticoagulant for chronic therapy. There have been several case reports of cranberry juice or cranberry sauce potentiating the effects of warfarin by elevating the INR; however, clinical trials evaluating this interaction have failed to demonstrate a significant effect on an INR.
Our case report describes INR elevations in a patient previously stable on warfarin after ingestion of cranberry juice cocktail daily for several days. This elevation occurred on 2 separate occasions, which distinguishes our case from other published literature.
报告 1 例华法林与蔓越莓汁相互作用导致国际标准化比值（INR）升高的病例。
1 例 46 岁女性患者，接受每周 56mg 的华法林治疗。在事件发生前的 4 个月内，INR 平均为 2.0，范围为 1.6-2.2，同时服用相同剂量的华法林。连续 2 天每天饮用约 1.5 夸脱（1420 毫升）蔓越莓汁鸡尾酒，其 INR 升高至 4.6。14 天后未饮用蔓越莓汁鸡尾酒时，INR 为 2.3。接下来的 3 个月，在每周服用 56mg 华法林期间，INR 平均为 2.1，范围为 1.4-2.5。随后在连续 3-4 天每天饮用约 2 夸脱（1893 毫升）蔓越莓汁鸡尾酒后，INR 升高至 6.5。停止服用华法林 3 天后，INR 为 1.86。恢复每周 56mg 华法林剂量 7 天后，INR 为 3.2。在两次 INR 升高期间，未发现其他可能导致 INR 升高的因素，如药物、草药、疾病或其他食物相互作用。客观因果关系评估显示，该相互作用极有可能发生。
华法林是慢性治疗最常用的抗凝剂。已有几例报告称，蔓越莓汁或蔓越莓酱通过升高 INR 增强华法林的作用；然而，评估这种相互作用的临床试验未能证明对 INR 有显著影响。
我们的病例报告描述了 1 例患者在连续几天每天饮用蔓越莓汁鸡尾酒后，华法林稳定治疗期间 INR 升高。这种升高发生在 2 次不同的情况下，这使我们的病例与其他已发表的文献有所区别。
