RESUMO
<b>Objectives</b> : A pharmacotherapeutic system for safe and proper use of warfarin was developed through physician-pharmacist cooperative practice ; its effects on patient adherence to therapeutic regimens and the therapeutic benefit of warfarin were assessed.<br><b>Methods</b> : Subjects were 12 outpatients or home-care patients receiving warfarin. Patients' level of understanding of warfarin therapy and time in therapeutic range (TTR) were used as indices of adherence and therapeutic benefit, respectively. Before the physician examination, patients were interviewed by pharmacists using point-of-care testing with the CoaguChek <sup>®</sup>XS to check their prothrombin time-international normalized ratio (PT-INR). Pharmacists reported status of warfarin administration, any adverse effects, and medication management status to each patient's physician using the medication record or inter-institute information exchange sheet. Patient adherence was assessed before and after the pre-examination interview and changes in TTR were evaluated.<br><b>Results</b> : Levels of understanding of warfarin therapy were significantly higher after pharmacists provided medication counseling (immediately before 4.8±1.9 vs 24 weeks after 6.8±2.4 ; P=0.0079, Wilcoxon signed-rank test). TTR significantly improved at 24 weeks after the interview (pre-interview 20.9±29.8% vs post-interview 60.5±30.5%, respectively ; P=0.0024, Wilcoxon signed-rank test).<br><b>Conclusion</b> : The results suggest that patients'adherence to warfarin regimens and the therapeutic benefit of warfarin is improved by pharmacists'obtaining information on PT-INR before patients'medical examinations, as well as by utilizing this information to establish a cooperative pharmacotherapeutic system for good TTR management, as supported by a common protocol across pharmacies and medical institutions.