Smith J K, Aljazairi A, Fuller S H
Salem Veterans Affairs Medical Center, WA, USA.
Ann Pharmacother. 1999 Mar;33(3):301-4. doi: 10.1345/aph.18171.
To report a case of international normalized ratio (INR) prolongation in a patient receiving warfarin who experienced several episodes of diarrhea.
A 56-year-old white woman, previously controlled on warfarin therapy (INR 2.5-3.5) after aortic valve replacement, experienced six episodes of INR elevation, each associated with an acute bout of diarrhea lasting from one to four days. The patient had not received additional warfarin or new medications (including nonprescription medications and herbal remedies) prior to the episodes. The patient had no obvious signs of bleeding (except bruising on 1 episode) or signs of infection determined through physician evaluation of the patient and her stools. In addition, she had no diagnosis of liver disease or acute or chronic malabsorption. The patient did report that her dietary intake decreased to 25-50% of normal during these episodes of diarrhea, which may result in decreased vitamin K ingestion.
This is one of the first case reports documenting a trend of INR elevation specifically with episodes of diarrhea. Since most of the common reasons for acute INR elevation have been eliminated, diarrhea with decreased oral intake are the most probable causes for these observed changes in the INR. Several reports suggest that acute diarrhea results in malabsorption of vitamin K, which can predispose patients taking warfarin to INR elevations, but in many of these reports patients had other risk factors for INR elevation. Although the effect of diarrhea on vitamin K absorption and the INR is difficult to quantify, the INR elevation reported here seemed to be directly associated with the duration of each diarrheal episode.
Diarrhea episodes in patients receiving warfarin can result in prolongation of the INR and possible bleeding. Patients who experience diarrhea or decreased oral intake resulting in elevated INRs should have their INRs evaluated more frequently and their warfarin doses adjusted appropriately.
报告1例接受华法林治疗的患者出现国际标准化比值（INR）延长的病例，该患者经历了数次腹泻发作。
一名56岁白人女性，在主动脉瓣置换术后一直接受华法林治疗（INR为2.5 - 3.5），出现了6次INR升高，每次均与持续1至4天的急性腹泻发作相关。在这些发作之前，患者未服用额外的华法林或新药物（包括非处方药和草药）。通过医生对患者及其粪便的评估，患者没有明显的出血迹象（除了1次发作时有瘀伤）或感染迹象。此外，她没有肝病诊断，也没有急性或慢性吸收不良。患者确实报告在这些腹泻发作期间，她的饮食摄入量降至正常的25% - 50%，这可能导致维生素K摄入减少。
这是首批记录INR升高趋势特别是与腹泻发作相关的病例报告之一。由于急性INR升高的大多数常见原因已被排除，口服摄入量减少的腹泻是这些观察到的INR变化的最可能原因。几份报告表明，急性腹泻会导致维生素K吸收不良，这可能使服用华法林的患者易发生INR升高，但在许多这些报告中，患者有其他INR升高的危险因素。虽然腹泻对维生素K吸收和INR的影响难以量化，但此处报告的INR升高似乎与每次腹泻发作的持续时间直接相关。
接受华法林治疗的患者发生腹泻可能导致INR延长并可能出血。经历腹泻或口服摄入量减少导致INR升高的患者应更频繁地评估其INR，并适当调整华法林剂量。
