F2 and blood coagulation disease: Despite discontinuing warfarin before NR application (NR was used on the first day of warfarin withdrawal), one patient experienced an increased international normalized ratio (INR; 5.32 (0.90–1.20)), prothrombin time (PT; 62.8 (9.4–12.5) s), and activated partial thromboplastin time (aPTT; 66.1 (25.1–36.5) s), as well as an increased fibrinogen level (425 (200–400) mg/dL) and coagulation disorders (weak positive fecal occult blood test) on the second day after using NR.