Warfarin Pharmacogenetics

Genetic Study of
Warfarin Pharmacogenetics

Evaluation of warfarin pharmacokinetics and pharmacodynamics



 Is the most widely used oral anticoagulant.


Is among the most effective agents in preventing thromboembolic events.


Its dosage should be carefully monitored in order to obtain maximum therapeutic benefits.


Why taking warfarin could be a problem? 

+ Highly variable patient response to Warfarin

+ Adverse side-effects of non-optimal Warfarin dosage.

Genetic Study of Warfarin


Evaluation of the genotypes that affect Warfarin metabolism.

The utility of genetic testing is recognized in guidelines related to the management of Warfarin therapeutics.

It is recommended for:

icon-check-trombogene  Individuals with a personal history of adverse drug reactions to warfarin;

icon-check-trombogene  Individuals receiving warfarin therapy in a clinical context of thromboembolic diseases, pulmonary thromboembolism, stroke or myocardium infarction, among others.

Benefits of Genetic Study of Warfarin Pharmacogenetics


1. Targeted 
Identifying responders and non-responders to drug exposure;

2. Simple 
A sample of blood or saliva is enough to perform the genetic test.

3. Preventive  
Minimizes the risk for bleeding and blood clot formation avoiding adverse events.




4. Personalised
Optimizing drug dose according to each person genetic profile

5. Effective
Reduce patients morbidity and healthcare costs due to non-adequate Warfarin therapeutics

6. Complete
Evaluates all 18 possible haplotipes

Start improving the treatment with Warfarin today

(Only for registered medical doctors, register here)

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Warfarin Pharmacogenetics

Scientific Background


1. Warfarin Intro 

Warfarin efficacy is highly dependent on achieving and maintaining a narrow therapeutic window, usually an international normalized ratio (INR) between 2 and 3. Its use is associated with increased risk of blood clot formation when treatment is subtherapeutic (INR of less than 2) or bleeding when supratherapeutic (INR of 4 or more).

The increased serum warfarin levels is a reflection of patients overmedication, increasing the INR above the therapeutic target level and accounting for increased bleeding incidents in some patients.

Clinical factors, demographic variables and variations in CYP2C9 and VKORC1 genes contribute significantly to the variability among patients in dose requirements for Warfarin.

2. Key Protein and genes 

CYP2C9 – Cytochrome P450, Family , Subfamily C, Polypeptide 9

Is a member of the cytochrome P450 superfamily with a significant action in Warfarin metabolism.

VKORC1 – Vitamine K Epoxide Reductase Complex, Subunit 1

Encodes the Vitamin K-epoxide reductase, which catalyses the rate-limitin step in vitamin K recycling: the conversion of vitamin K-epoxide to vitamin K.

3. Warfarin genetic painel

The warfarin genetic test developed by HeartGenetics includes the evaluation of 2 genetics variants in CYP2C9 gene and 1 genetic variant in VKORC1 gene.


4. How Genetic variants are selected


Our research is supported by peer review papers that have been published in the reference journals in the field.


All genetic variants have been validated in reference databases (HGMDP, NCBI-OMIM, NCBI-ClinVar, NCBI-Variation Reporter and Ensembl).


The knowledge in our databases was approved by internationally recognized medical geneticist and cardiologists.

5. International Guidelines

In this context, the FDA approved a labeling change for warfarin that describes the effects of VKORC1 and CYP2C9 genetic variants on warfarin dose requirements.

Also, the Clinical Pharmacogenetics Implementation Consortium (CPIC) of the National Institutes of Health Pharmacogenomics Research Network develops peer-reviewed gene–drug guidelines that are published and updated periodically based on new developments in the field [2,9]. 

6. HeartGenetics’ Warfarin Pharmacogenetics reports


The Warfarin pharmacogenetics panel includes genetic variants associated with variability in Warfarin sensibility and the increased relative risk of bleeding.


The used technology has a 99% of accuracy.

All evidences are supported by updated scientific knowledge and validated by medical doctors.


All results include supporting information for each genetic variant including scientific references to guide the interpretation of test results.

HeartGenetics reports follow the recommendations from the European Society of Human Genetics

European Society of Human Genetics.

Contact us here for a report example.

Start improving the treatment with Warfarin today

(Only for registered medical doctors, register here)

Download Warfarin Requisition Form: PT | EN

Go back to products  |  Download Product Sheet  |  Need further information? Contact us

Selected references

[1] Food and Drug Administration webpage: http://www.fda.gov/

[2] Clin Pharmacol Ther. 2011. 90(4):625-9. Clinical Pharmacogenetics Implementation Consortium Guidelines for CYP2C9 and VKORC1 genotypes and warfarin dosing.

[3] Clin Cardiol. 2014. 37(1):48-56. Pharmacogenetics in cardiovascular disease: the challenge of moving from promise to realization: concepts discussed at the Canadian Network and Centre for Trials Internationally Network Conference (CANNeCTIN), June 2009.

[4] N Engl J Med. 2009. 360(8):753-64. Estimation of the warfarin dose with clinical and pharmacogenetic data.

[5] PLoS One. 2012. 7(8):e44064. Influence of CYP2C9 and VKORC1 on patient response to warfarin: a systematic review and meta-analysis.

[6] Mayo Clin Proc. 2009. 84(12):1079-94. Warfarin sensitivity genotyping: a review of the literature and summary of patient experience.

[7] Annu Rev Med. 2010. 61:63-75. Pharmacogenetics of warfarin.

[8] N Engl J Med. 2005. 352(22):2285-93. Effect of VKORC1 haplotypes on transcriptional regulation and warfarin dose.

[9] http://www.accessdata.fda.gov/drugsatfda_docs/label/2011/009218s107lbl.pdf