Navigation Links
Genetics Determine Optimal Drug Dose of Common Anticoagulant

WASHINGTON, Aug. 21 /PRNewswire-USNewswire/ -- Genetic testing can be used to help personalize the therapeutic dosage of warfarin, a commonly-used anticoagulant, according to research published in the September 1, 2007, issue of Blood, the journal of the American Society of Hematology. This result represents one of the first applications of using an individual's genetic information to guide personal medical care.

Because individuals metabolize drugs differently, varying doses of warfarin are needed for the drug to be effective in each patient. Too much warfarin can cause severe bleeding, and too little can cause dangerous blood clots. Currently, there is little guidance for predicting how much of the drug a person will need. Physicians have had to roughly estimate an initial dose of warfarin and then continually monitor a patient's International Normalized Ratio (INR) value (a measure of how fast the blood clots), during treatment to tweak the dosage by trial and error.

For the first time, a group of St. Louis researchers combined the standard INR method with genetic testing to predict the therapeutic warfarin dose. Since warfarin is often prescribed after major orthopedic surgery to prevent blood clots in the legs, the study followed 92 adults undergoing either total hip or knee replacement at the Washington University Medical Center, who had never previously taken the anticoagulant.

Prior to warfarin treatment, the researchers collected blood samples and each patient's medical history. The blood tests were used to examine variations in two genes, CYP2C9 and VKORC1, that may affect warfarin dosing. Variants in CYP2C9 impair the body's breakdown of warfarin; variants in VKORC1 cause increased warfarin sensitivity. The patients were assigned initial doses of warfarin based on clinical factors and their genotype. The researchers followed the patients until successful treatment outcomes were achieved several weeks later.

By combining variants in these genes with initial INR response and other clinical factors, the researchers derived a dosing equation that estimated the therapeutic warfarin dose. The researchers found that these two genes were important in predicting the response to warfarin. Additional factors, such as blood loss during surgery and smoking status, also correlated with therapeutic dose.

Using these data, the researchers developed a therapeutic model that could be used by physicians to refine warfarin dosage with greater accuracy than clinical factors alone. The researchers have made this dosing model publicly available on a free Web site,, and are now validating it in orthopedic and non-orthopedic patients beginning warfarin therapy.

If validated, particularly in patients taking warfarin for reasons other than orthopedic surgery, such as to prevent stroke, this gene-based dosing could predict a safe and effective warfarin dose at the start of treatment, thus minimizing the risks of the current trial-and-error approach.

This work was funded by the National Institutes of Health.

Reporters who wish to receive a copy of the study or arrange an interview with Brian F. Gage, MD, MSc, lead author of the study, may contact Laura Stark at 202-776-0544 or

The American Society of Hematology ( is the world's largest professional society concerned with the causes and treatment of blood disorders. Its mission is to further the understanding, diagnosis, treatment, and prevention of disorders affecting blood, bone marrow, and the immunologic, hemostatic, and vascular systems, by promoting research, clinical care, education, training, and advocacy in hematology.

Blood, the official journal of the American Society of Hematology, is the most cited peer-reviewed publication in the field. Blood is issued to Society members and other subscribers twice per month, available in print and online at

SOURCE American Society of Hematology
Copyright©2007 PR Newswire.
All rights reserved

Related medicine technology :

1. Response Genetics Announces Publication of a Phase III Clinical Trial Demonstrating That Low Levels of ERCC-1 Help to Predict Likelihood of Response to Cisplatin-Based Therapy in Lung Cancer
2. Genetics Journal Thimerosal/Autism Study the Best Science Drug Company Money Can Buy
3. Targeted Genetics Reports Inflammatory Arthritis Clinical Data at European Rheumatology Conference
4. Myriad Genetics Presents Mathematical Comparison of Disease Modification Trial Designs at Alzheimers ConferenceCurrent Flurizan Phase 3 Study Design May Demonstrate Disease Modification
5. Vion Pharmaceuticals Presents Clinical Data from a Phase II Trial of Cloretazine (VNP40101M) in Elderly AML Patients with Unfavorable Cytogenetics at EHA Meeting
6. ZymoGenetics Reports Results From Atacicept Phase 1b Clinical Trial in B-Cell Chronic Lymphocytic Leukemia
7. Myriad Genetics Presents Tumor Origin Technology at AACR
8. Seattle Genetics Highlights Data on its Proprietary Antibody-Drug Conjugate Technology at AACR
9. Aeolus Pharmaceuticals AEOL 10150 Highlighted in Nature Genetics Publication
10. Myriad Genetics Presents Azixas Mode of Action at AACR
11. Expression Genetics, Inc. Announces Successful Completion of Phase I Trial of Gene-Based IL-12 for Treatment of Ovarian Cancer
Post Your Comments:
(Date:6/24/2016)... , June 24, 2016   Bay Area ... Network,s Dean Center for Tick Borne Illness ... and Rehabilitation, MIT Hacking Medicine, University of California, ... today announced the five finalists of Lyme ... disease.  More than 100 scientists, clinicians, researchers, entrepreneurs, ...
(Date:6/24/2016)... The Academy of Managed Care Pharmacy (AMCP) ... would allow biopharmaceutical companies to more easily share health ... and coverage decisions, a move that addresses the growing ... The recommendations address restrictions in the sharing of ... label, a prohibition that hinders decision makers from accessing ...
(Date:6/24/2016)... Research and Markets has announced the addition of ... report to their offering. ... The World Market for Companion Diagnostics covers the world market ... the report includes the following: , World ... Region (N. America, EU, ROW), 2015-2020 , World IVD ...
Breaking Medicine Technology:
(Date:6/27/2016)... Viejo, California (PRWEB) , ... June 27, 2016 , ... ... are fully customizable inside of Final Cut Pro X," said Christina Austin - CEO ... another unique style. Final Cut Pro X users can now reveal the ...
(Date:6/27/2016)... Brooklyn, NY (PRWEB) , ... June 27, 2016 ... ... is using cutting edge technology to revolutionize the emergency ambulance transport experience for ... Many are aware of how Uber has disrupted the taxi industry through the ...
(Date:6/26/2016)... , ... June 26, 2016 , ... On June 10-11, ... of the 2016 Cereal Festival and World’s Longest Breakfast Table in Battle Creek, MI, ... the city’s history as home to some of the world’s leading providers of cereal ...
(Date:6/26/2016)... NC (PRWEB) , ... June 26, 2016 , ... Brent Kasmer, a legally blind and ... to be personalized through a fitness app. The fitness app plans to fix the two ... currently only offer a one size fits all type program , They don’t ...
(Date:6/25/2016)... , ... June 25, 2016 , ... Austin residents seeking ... American College of Mohs Surgery and to Dr. Russell Peckham for medical and surgical ... effective treatment for skin cancer. The selective fellowship in Mohs Micrographic Surgery completed by ...
Breaking Medicine News(10 mins):