A woman in her seventies who was started on warfarin after heart valve replacement began outpatient adjuvant chemotherapy with tegafur-uracil/leucovorin for rectal cancer. The patient performed weekly INR self-measurements at a health insurance pharmacy between outpatient visits. Results recorded in her personal medicine notebook were shared between her physician, a hospital pharmacist, and a pharmacy pharmacist. When INR values were outside the therapeutic target range, doses were altered according to the physician's instruction. Our approach enables the fine adjustment of warfarin doses according to changes in INR and contributes to the maintenance of the therapeutic target range and safe and appropriate outpatient chemotherapy.
Keywords: INR self‐measurement; tegafur‐uracil/leucovorin; time in the therapeutic range; warfarin.