Biological and Pharmaceutical Bulletin
Online ISSN : 1347-5215
Print ISSN : 0918-6158
ISSN-L : 0918-6158
Change of the Blood Concentration of Tacrolimus after the Switch from Fluconazole to Voriconazole in Patients Receiving Allogeneic Hematopoietic Stem Cell Transplantation
Hitoshi KawazoeYoshiharu TakiguchiHiroaki TanakaNoriyasu FukuokaHiroaki OhnishiToshihiko IshidaHitoshi Houchi
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2006 Volume 29 Issue 12 Pages 2528-2531


The purpose of this study was to assess the impact by switching co-administered triazole antifungal agent from fluconazole (FCZ) to voriconazole (VCZ) on the blood concentration of tacrolimus (FK506) in patients receiving allogeneic hematopoietic stem cell transplantation. We performed a retrospective study presented as case reports. The blood concentration of FK506 was increased after the switch from FCZ to VCZ, resulting in increase of the concentration/dose (C/D) ratio of FK506. Thus, the mean C/D ratios of FK506 with oral administration was surprisingly increased over 4.5-fold after the switch. Therefore, it was necessary to reduce the FK506 dose when co-administered FCZ is switched to VCZ. We should be careful when interpreting the results of these case reports; however, in some patients, it is recommended that the dose of FK506 be reduced to one-fifth after the switch.

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© 2006 The Pharmaceutical Society of Japan
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