Pharmacogenetic Dosing of Warfarin

Summary

Purpose: Warfarin is now the most commonly used oral anticoagulant. This drug has inter-individual variability due to the genetic polymorphisms in the warfarin metabolizing enzyme, CYP2C9 and warfarin target, VKORC1. The investigators' team developed a pharmacogenetic dosing algorithm which can predict patients required warfarin dose, thus could prevent warfarin induced warfarin adverse events. Methods: The investigators recruited patients with indications for warfarin, the genotypes of VKORC1 and CYP2C9 were determined by the hospitals and verified by National Center for Genome Medicine. The investigators then randomized the patients to one of three arms: 1. Warfarin dose predicted by dosing algorithm developed by the International Warfarin pharmacogenetic Consortium (IWPC), 2. Algorithm developed by the Taiwan Warfarin Consortium and 3. Standard of care. The investigators aimed to determine whether using genetic dosing algorithm can lead to more stable dose and safer use of the drug.

Timeline

Start

2009-09

Primary completion

2013-12

Completion

2013-12

Publications

• Ohara M, Takahashi H, Lee MT, Wen MS, Lee TH, Chuang HP, Luo CH, Arima A, Onozuka A, Nagai R, Shiomi M, Mihara K, Morita T, Chen YT. Determinants of the over-anticoagulation response during warfarin initiation therapy in Asian patients based on population pharmacokinetic-pharmacodynamic analyses. PLoS One. 2014 Aug 22;9(8):e105891. doi: 10.1371/journal.pone.0105891. eCollection 2014.

Drugs

Indications