Evaluation of CYP2C9- and VKORC1-based pharmacogenetic algorithm for warfarin dose in Gaza-Palestine

AIM: To evaluate applicability of CYP2C9*2, *3 and VKORC1–1639G > A based algorithm to predict warfarin stable dose (WSD) in a group of Palestinian patients. PATIENTS & METHODS: Warfarin doses were retrospectively calculated for 101 Palestinian patients under warfarin therapy using three models. Performance of the three models was assessed in 47 patients found to take WSD. RESULTS: Frequency of CYP2C9*2, *3 and VKORC1–1639G > A alleles is 13.6, 0.0 and 46.5% respectively. The international warfarin pharmacogenetics consortium algorithm was more reliable (MAE = 8.9 ± 1.4; R(2) = 0.350) than both the clinical algorithm (MAE = 10.4 ± 1.4; R(2) = 0.128;) and the fixed-dose algorithm (MAE = 11.1 ± 1.7). CONCLUSION: The international warfarin pharmacogenetics consortium algorithm can be reliably applied for predicting the WSD in Palestinian population.