Objective: To compare effects of the fluoropyrimidines S-1 and capecitabine on prothrombin time international normalized ratios (PT-INR) of warfarin following coadministration and after discontinuation of each fluoropyrimidine treatment.
Methods: Medical records of patients receiving warfarin with either S-1 (6 patients) or capecitabine (7 patients) were obtained from four hospitals.
Results: Increased PT-INR was observed until peak levels of warfarin were achieved in all patients in S-1 and capecitabine treatment groups.　Moreover, PT-INR significantly changed after coadministration within each group (p＜0.05).　Specifically, ratios of peak PT-INR after coadministration of each fluoropyrimidine and those following administration of warfarin alone (PT-INR elevation ratio) were 3.31 and 3.29 in S-1 and capecitabine coadministration groups, respectively.　Moreover, numbers of days to peak PT-INR were 38.3 and 31.3 days, respectively, and did not significantly differ between the treatment groups.　Furthermore, PT-INR returned to pretreatment levels by 17.5 and 15.1 days after discontinuation of S-1 and capecitabine, respectively, and did not significantly differ between the treatment groups.
Conclusion: Coadministration of S-1 and capecitabine similarly prolongs PT-INR by approximately 3-fold compared with administration of warfarin alone; therefore, these drug-drug interactions were clinically suggested to be of high risk for episodes of bleeding and remarkable alterations in coagulation parameters.　Therefore, blood coagulation ability should be more carefully monitored with regard to PT-INRs in patients receiving warfarin with S-1 or capecitabine not only during coadministration but also after discontinuation of fluoropyrimidine treatments.

Cough is one of the most common respiratory complaints leading to medical consultation. Fractional exhaled nitric oxide (FeNO) testing detects eosinophilic inflammation of the airway. We evaluated the diagnostic efficacy of FeNO testing in patients with cough. Patients who presented to the respiratory medicine department of our hospital with a chief complaint of cough and underwent FeNO testing were included in this study and divided into asthma and non-asthma groups. Patients with confounding factors such as allergic rhinitis and atopic predispositions were also identified and those with and without confounding factors, respectively, were further divided into the asthma and non-asthma groups. Median FeNO in the asthma and non-asthma groups was respectively 31 and 19 ppb in all patients and 31 and 18 ppb in those without confounding factors, with significant differences between the groups in both populations. The corresponding values in patients with confounding factors were 46 and 23 ppb, with no significant difference between the groups. A cut-off of 27 ppb differentiated between the asthma and non-asthma groups with sensitivity of 0.603 and specificity of 0.776. These results suggest FeNO testing is effective in the differential diagnosis of cough in patients without confounding factors.