Featured Research

from universities, journals, and other organizations

FDA Approves Genetic Testing Labeling For Blood-thinning Drug

Date:
August 18, 2007
Source:
U.S. Food and Drug Administration
Summary:
The U.S. Food and Drug Administration has announced the approval of updated labeling for the widely used blood-thinning drug, Coumadin, to explain that people's genetic makeup may influence how they respond to the drug. Manufacturers of warfarin, the generic version of Coumadin, are to add similar information to their products' labeling.

The U.S. Food and Drug Administration has announced the approval of updated labeling for the widely used blood-thinning drug, Coumadin, to explain that people's genetic makeup may influence how they respond to the drug.

Manufacturers of warfarin, the generic version of Coumadin, are to add similar information to their products' labeling, FDA said.

The labeling change highlights the opportunity for healthcare providers to use genetic tests to improve their initial estimate of what is a reasonable warfarin dose for individual patients. Testing may help optimize the use of warfarin and lower the risk of bleeding complications from the drug.

These labeling updates are based on an analysis of recent studies that found people respond to the drug differently based, in part, on whether they have variations of certain genes.

FDA estimates that 2 million persons start taking warfarin in the United States every year to prevent blood clots, heart attacks and stroke. Warfarin is a difficult drug to use because the optimal dose varies and depends on many risk factors including a patient's diet, age, and the use of other medications.

Patients who take a dose larger than they can tolerate are at risk of life-threatening bleeding. Those who receive too low a dose are at risk of equally dangerous blood clots. Dosing is particularly important at the beginning of therapy, when problems in adjusting the dose can lead to complications such as bleeding.

Warfarin is the second most common drug – after insulin –implicated in emergency room visits for adverse drug events.

Physicians and other health care professionals who prescribe warfarin regularly check to see if the drug is working properly by ordering a test called the PT or prothrombin time that evaluates the blood's ability to clot properly. The results are measured in seconds and compared with the expected value in healthy people, known as the International Normalized Ratio or INR.

"Today's approved labeling change is one step in our commitment to personalized medicine. By using modern science to get the right drug in the right dose for the right patient, FDA will further enhance the safety and effectiveness of the medicines Americans depend on," said Commissioner of Food and Drugs Andrew C. von Eschenbach, M.D.

The FDA's "personalized medicine" initiative makes use of pharmacogenomics—the science that predicts a response to drugs based upon a person's genetic makeup. This effort supports the personalized health program spearheaded by Health and Human Services Secretary Mike Leavitt.

A person's genes "encode" enzymes and differences in the sequence of a gene can cause differences in enzyme activity or sensitivity. That is why different people process the same drug differently.

One-third of patients receiving warfarin metabolize it quite differently than expected. Research has shown that some of the unexpected response to warfarin depends on a patient's variants of the genes CYP2C9 and VKORC1.

"Although genetic testing can currently identify who has these genetic variants, more studies are needed to explore the precise starting dose for these patients," said Larry Lesko, Ph.D., director of the FDA's Office of Clinical Pharmacology. "FDA has been working with other government agencies and organizations to develop such studies under the auspices of our three-year-old Critical Path Initiative, which addresses the challenges of moving promising medical products from discovery to patient use."

FDA's Critical Path Initiative has funded a research project with the University of Utah and the Critical Path Institute of Tucson, Ariz., to develop genetically based instructions for warfarin dosing. The Initiative has also facilitated meetings and planning with the National Heart, Lung and Blood Institute for a clinical trial that will study warfarin dosing based on genetic test information and is helping to pay for another clinical study being conducted by Harvard Partners that will derive personalized warfarin dosing algorithms for patients new to the drug.

The dosage and administration of warfarin must be individualized for each patient according to the particular patient's PT/INR response to the drug. The specific dose recommendations are described in the warfarin product labeling, along with the new information regarding the impact of genetic information upon the initial dose and the response to warfarin. Ongoing warfarin therapy should be guided by continued INR monitoring.

Bristol-Myers Squibb Co. of Princeton, N.J., is the manufacturer of Coumadin.


Story Source:

The above story is based on materials provided by U.S. Food and Drug Administration. Note: Materials may be edited for content and length.


Cite This Page:

U.S. Food and Drug Administration. "FDA Approves Genetic Testing Labeling For Blood-thinning Drug." ScienceDaily. ScienceDaily, 18 August 2007. <www.sciencedaily.com/releases/2007/08/070817113120.htm>.
U.S. Food and Drug Administration. (2007, August 18). FDA Approves Genetic Testing Labeling For Blood-thinning Drug. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2007/08/070817113120.htm
U.S. Food and Drug Administration. "FDA Approves Genetic Testing Labeling For Blood-thinning Drug." ScienceDaily. www.sciencedaily.com/releases/2007/08/070817113120.htm (accessed August 21, 2014).

Share This




More Health & Medicine News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
Ramen Health Risks: The Dark Side of the Noodle

Ramen Health Risks: The Dark Side of the Noodle

AP (Aug. 21, 2014) South Koreans eat more instant ramen noodles per capita than anywhere else in the world. But American researchers say eating too much may increase the risk of diabetes, heart disease and stroke. (Aug. 21) Video provided by AP
Powered by NewsLook.com
Possible Ebola Patient in Isolation at California Hospital

Possible Ebola Patient in Isolation at California Hospital

Reuters - US Online Video (Aug. 20, 2014) A patient who may have been exposed to the Ebola virus is in isolation at the Kaiser Permanente South Sacramento Medical Center. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins