著者

Masayuki Ikenishi Akiko Kuroda Haruhiko Tsukazaki Masahiko Nakao Masashi Takeuchi Yuji Konishi Toshiyuki Matsuda Tohru Ohtori Kenji Matsuyama Mitsutaka Takada Hiroki Satoh Yasufumi Sawada Mutsuaki Ueda

出版者

一般社団法人日本医薬品情報学会

雑誌

医薬品情報学 (ISSN:13451464)

巻号頁・発行日

vol.18, no.3, pp.172-178, 2016 (Released:2017-02-14)

参考文献数

32

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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.

著者

Sayoko Kinoshita Kyoichi Wada Sachi Matsuda Takeshi Kuwahara Haruki Sunami Takuma Sato Osamu Seguchi Masanobu Yanase Takeshi Nakatani Mitsutaka Takada

出版者

一般社団法人 日本内科学会

雑誌

Internal Medicine (ISSN:09182918)

巻号頁・発行日

vol.55, no.7, pp.719-724, 2016 (Released:2016-04-01)

参考文献数

25

被引用文献数

2 4

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Objective The purpose of this study was to investigate the possible interaction between warfarin and linezolid in patients with a left ventricular assist system (LVAS) for the treatment of severe heart failure. Methods Patients with LVAS who were treated with linezolid for the treatment of infections from January 2003 to March 2013 were identified from medical records. The impact of linezolid on the clotting function, as well as the dose of warfarin during the first 10 days of linezolid therapy, was investigated. The mean prothrombin time-international normalized ratio (PT-INR) and mean doses of warfarin during 7 days before and 10 days after the initiation of linezolid therapy were calculated for individual patients. The PT-INR per mg of WF dose on the previous day (X) was calculated. The warfarin dose, PT-INR, and warfarin sensitivity index (WSI) value before and after the initiation of linezolid were compared to evaluate the impact of linezolid on the effect of warfarin. Results Sixteen patients were enrolled in the study. Although the mean PT-INR increased from 3.74 to 4.06, no significant difference was observed (p=0.05). A significant difference was observed in the mean dose of warfarin before and after the initiation of linezolid administration, with a decrease from 3.23 to 2.69 mg/day (p=0.001). In contrast, the mean WSI value significantly increased from 1.37 to 1.82 (p=0.014). After 10 days of linezolid administration, the mean X values increased over the baseline value by 31.7%. Conclusion These findings suggest that co-administration of linezolid results in increased PT-INR in patients with LVAS treated with warfarin.