PMID: 11918508Mar 29, 2002Paper

Effect of stress on international normalized ratio during warfarin therapy

The Annals of Pharmacotherapy
Toni L Hawk, D E Havrda

Abstract

To discuss the effect of stress on the international normalized ratio (INR) when patients are taking warfarin. Two patients at a pharmacist-managed anticoagulation clinic who were stable with anticoagulation developed elevated INR values after a stressful event occurred. All other factors known to elevate the INR were unchanged; furthermore, the INR values returned to the prior level of control after resolution of the stressful events. Management of anticoagulation with warfarin requires the knowledge of factors that may alter an INR. Many of these factors, such as dietary changes, illnesses, drug interactions, patient compliance, and physical activity, have been described. In spite of this understanding, many patients continue to experience variability in their INR values, suggesting there are other factors that can alter the INR that have not been fully described. The cases presented here demonstrate that stressful events, physical or psychological, can elevate the INR. The mechanism for this occurrence is unknown, but may be related to decreased metabolism of warfarin during stress. When an unexplained INR value exists, a stressor should be evaluated as a potential cause.

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Citations

Aug 3, 2013·Journal of Clinical Pharmacology·Li AnSrinivas Denduluri
Dec 21, 2013·Journal of Thrombosis and Haemostasis : JTH·Y F LaiH J Ng
Mar 21, 2006·High Altitude Medicine & Biology·Martha C Tissot Van PatotM D Salman
Jan 5, 2006·American Journal of Health-system Pharmacy : AJHP : Official Journal of the American Society of Health-System Pharmacists·Kyoung A MinWan G Shin
Oct 1, 2011·Expert Opinion on Drug Safety·Heather D EdwardsSusan E Conway
May 30, 2003·The Annals of Pharmacotherapy·William E Dager

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