An analysis of the interactions between warfarin and Korean traditional herbal medicine in a Korean oriental hospital

IntroductionWarfarin is an anticoagulant and information on its interactions with herbal medicine is limited. The aim of this research was to explore the interactions between warfarin and herbal medicines by studying inpatients in an oriental hospital over one year.MethodsPatients admitted to Dongguk University Ilsan Oriental Hospital between June 1, 2010 and June 30, 2011 were identified using the through EMR (Electronic Medical Record) system. Cases of reported interactions were searched using the WHO UMC scale (World Health Organization Uppsala Monitoring Centre causality categories) and the mDIP scale (Modified Drug Interaction Probability Scale), and the level of causation evaluated.Results82 kinds of herbal medicines were prescribed to 27 patients. Using the standard of the mDIP scale, 1 probable (level of causation) interaction case and 3 possible (level of causation) interaction cases were identified (an incidence of 5%). Using the WHO-UMC scale, 2 probable interaction cases and 6 possible interaction cases were identified (an incidence of 10%).ConclusionThis study identified several cases of potential interactions between warfarin and herbal medicine had been reported. Patients should be encouraged and educated to report adverse events and clinicians should measure PT/INR (prothrombin time/international normalized ratio) when herbal medicines are prescribed to patients taking warfarin.This article belongs to the Special Issue: “Ensuring and Improving Patients' Safety in Integrative Health Care”.