Anticoagulation Intensity of Rivaroxaban for Stroke Patients at a Special Low Dosage in Japan

作者：Okata Takuya; Toyoda Kazunori^*; Okamoto Akira; Miyata Toshiyuki; Nagatsuka Kazuyuki; Minematsu Kazuo

来源：PLos One, 2014, 9(11): e113641.

DOI：10.1371/journal.pone.0113641

Objectives: In Japan, low-dose rivaroxaban [15 mg QD/10 mg QD for creatinine clearance of 30-49 mL/min] was approved for clinical use in NVAF patients partly because of its unique pharmacokinetics in Japanese subjects. The aim of the study was to determine the anticoagulation intensity of rivaroxaban and its determinant factors in Japanese stroke patients.
Methods: Consecutive stroke patients with NVAF admitted between July 2012 and December 2013 were studied. Prothrombin time (PT), activated partial thromboplastin time (aPTT), and estimated plasma concentration of rivaroxaban (C-riv) based on an anti-factor Xa chromogenic assay were measured just before and 4 and 9 h after administration at the steady state level of rivaroxaban. Determinant factors for C-riv were explored using a linear mixed-model approach.
Results: Of 110 patients (37 women, 75+/-9 years old), 59 took 15 mg QD of rivaroxaban and 51 took 10 mg QD. C-riv at 4 h was 186 ng/mL for patients taking 15 mg QD and 147 ng/mL for those taking 10 mg QD. Both PT and aPTT were positively correlated with C-riv. C-riv was 72% lower at 4 h in 15 patients receiving crushed tablets than in the other patients, and tablet crushing was significantly associated with lower C-riv (adjusted estimate -0.43, 95% CI -0.60 to -0.26) after multivariate-adjustment.
Conclusion: The anticoagulation effects of rivaroxaban in the acute stroke setting for Japanese NVAF patients were relatively low as compared with those in the ROCKET-AF and J-ROCKET AF trials. Tablet crushing, common in dysphagic patients, decreased C-riv.

• 出版日期2014-11-26