Abstract
Previously, warfarin potassium (WF) was only marketed in tablet form. When the dose needed to be prepared in a form other than tablets, it was necessary to either grind or cut the tablets. When grinding such tablets, some degree of drug loss occurred due to adherence to the grinders, mortar and pestles, and power folders. These issues were finally solved by the sale of fine-grain WF products. However, it was thought that the prothorombin time-international normalized ratio (PT-INR) might be increased in patients who changed from ground tablets to the administration of fine-grain WF. Therefore, we investigated the PT-INR of such cases while also comparing the findings in cases of patients continuously administered with WF in tablet form. The average PT-INR in patients that changed from the ground form to the administration of fine-grain WF was 1.81 (before the change) and 1.94 (after), thus showing a slight increase, but not one that was statistically significant. When the fluctuation range of PT-INR was compared with patients continuously taking WF tablets, the fluctuation ranges of PT-INR were 0.13 and 0.067, respectively, and no significant difference was observed. As a result, there is a possibility that the change to fine-grain WF may cause an increase in PT-INR, but such increase was restricted. In this study, an increase in PT-INR did not have any effect on the medical examination.
