Abstract

Application of pharmacogenetics in warfarin therapy at the

  Warinchamrab Hospital

 Rachata Mungkornkaew and Ronnachai Chommueang

Somwang Janyakhantikul, PhD;

Peerawat Jinathongthai (B.Sc.Pharm, BCP, BCPS)

 Warfarin, VKORC1, CYP2C9, Pharmacogenetics

ABSTRACT

TITLE            : Application of pharmacogenetics in warfarin therapy at the

                          Warinchamrab Hospital

AUTHORS     : Rachata Mungkornkaew and Ronnachai Chommueang

DEGREE       : Doctor of Pharmacy

MAJOR         : Pharmaceutical Sciences

CHAIRMAN    : Somwang Janyakhantikul, PhD;

                          Peerawat Jinathongthai (B.Sc.Pharm, BCP, BCPS)

KEYWORDS   : Warfarin, VKORC1, CYP2C9, Pharmacogenetics

Introduction: Warfarin is an anticoagulant drug using for treatment and prevention of thromboembolism. It has narrow therapeutic property and many factors have influence on warfarin response including genetic factor. There is evidence that the application use of pharmacogenetics is helpful in warfarin dosage adjustment. However, the prevalence and relationship of genetic character and warfarin response among Thai patients are still questionable. Objective: To compare the proportion of genotypes of genes which have effect to warfarin response between the groups of patient who have %TTR more than 40 and less than or equal to 40. Methods: 43 out-patients at medicine department of the Warinchamrab hospital, who were on warfarin at least for 3 months between Oct-Dec 2015, were collected for blood and DNA extraction. Then, the DNAs were analyzed for genotypes of CYP2C9*2 (CC, CA and AA), CYP2C9*3 (AA, AC and CC) and VKORC1 (GG, GA and AA). Difference in the proportion of genotypes in each gene between the two %TTR groups was determined by Chi-Square or Fisher exact. Results: In the group of patients who have %TTR more than 40, the frequencies of genotype CYP2C9*2 (C/C), CYP2C9*3 (A/A), VKORC1 (G/A) and VKORC1 (A/A) were 17 cases (100%), 17 cases (100%), 6 cases (35.29%) and 11 cases (64.71%), respectively. While in the group of patients who have %TTR less than or equal 40, the frequencies of genotype CYP2C9*2 (C/C), CYP2C9*3 (A/A), CYP2C9*3 (C/C), VKORC1 (G/G), VKORC1 (G/A), and VKORC1 (A/A) were 26 cases (100%), 24 cases (92.31%), 2 cases (7.69%), 3 cases (11.54%),10 cases (38.46%) and 3 cases (50%), respectively. Conclusion: There are no significant difference in the proportion of genotypes of CYP2C9*2, CYP2C9*3 and VKORC1 in between those two groups of patients in which the most genotypes are (C/C), (A/A) and (A/A), respectively.