Navigation Links
FDA Updates Prescription Guidelines for Blood Thinner
Date:8/18/2007

Gene variations dictate how quickly a patient metabolizes warfarin, officials say

THURSDAY, Aug. 16 (HealthDay News) -- The U.S. Food and Drug Administration announced Thursday a labeling update for the widely prescribed blood thinner warfarin (Coumadin), advising doctors that patients' genetic makeup can affect how they respond to the drug.

Responses to warfarin depend on a patient's variants of the genes CYP2C9 and VKORC1. About 30 percent of patients -- many of them heart patients -- who take warfarin have these gene variants.

These variations can determine how fast warfarin is metabolized, Larry Lesko, director of the FDA's office of clinical pharmacology at the Center for Drug Evaluation and Research, said during a teleconference. "Patients with these variations may need lower doses of warfarin than patients with the usual forms of these genes.

"The label change explains that certain people are likely to respond very differently to the drug if they happen to carry variations of two of their genes," Lesko said. The label updates are based on recent studies that found patients' response to the drug depends on these gene variations, he added.

In the United States, some 2 million people start taking warfarin every year to prevent blood clots, heart attacks and stroke, according to the FDA. Warfarin is tricky to use, because the correct dose varies and depends on risk factors, including diet, age, and other medications the patient is taking.

If the warfarin dose is too high, there is the risk of life-threatening bleeding. If the dose is too low, there is a risk of developing blood clots. Dosing is particularly important when starting the drug, the FDA said.

The FDA isn't mandating that doctors obtain genetic tests before prescribing warfarin but suggests that it is something doctors may want to consider when prescribing the drug.

"Doctors and other health-care professionals may well decide to incorporate genetic information along with more traditional risk factors in estimating their patient's warfarin doses," Lesko said. "It may improve the safe use of warfarin."

Lesko noted that genetic tests for the gene variants can cost $125 to $500. The tests may not be readily available in some parts of the United States, he said.

Dr. Janet Woodcock, the FDA's deputy commissioner and chief medical officer, noted during the teleconference that there isn't enough data to make genetic testing a mandate when prescribing warfarin.

"We have to test how good it will be to use genetic information versus the current methods, which are not perfectly satisfactory, but work to initiate warfarin therapy. Then we will have an answer to that question," Woodcock said.

Warfarin is the second most common drug to blame for emergency room visits for adverse drug events, after insulin, the FDA said.

Currently, patients need to have several blood tests over several weeks to determine their optimal warfarin dose.

Patients taking warfarin need to have their blood checked monthly to see if the drug is working properly. The test is called the PT -- or prothrombin time -- test, which evaluates the blood's ability to clot. The results are measured in seconds and compared with the expected value in healthy people.

The changes to the label will be made by manufacturers of warfarin, the generic version of Coumadin. Bristol-Myers Squibb Co., of Princeton, N.J., is the manufacturer of Coumadin, the FDA said.

More information

For more on warfarin, visit the U.S. National Library of Medicine.



SOURCES: Aug. 16, 2007, teleconference with Janet Woodcock, M.D., deputy commissioner and chief medical officer, U.S. Food and Drug Administration; Larry Lesko, Ph.D., director, office of clinical pharmacology, Center for Drug Evaluation and Research, U.S. Food and Drug Administration


'/>"/>

Copyright©2007 ScoutNews,LLC.

Related medicine news :

1. WHO Updates Outdated Pediatric Growth Charts
2. A prescription cream for unwanted facial hair
3. Lose Weight With New Wonder Slimming FDA approved Prescription Drug
4. Prescription Drug - Helps People Stop Smoking
5. Misleading Advertisements for Prescription Drugs
6. Patients Pressure Would Result In Overprescription
7. TV drug commercials prompt prescriptions
8. Prescription Drug Use Varies Widely Between States
9. Status of some prescription drugs
10. Abuse of prescription drugs among youths on the rise
11. Does Your Prescription Have An Inappropriate Medicine?
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/24/2016)... ... , ... A recent article published June 14 on E Online ... on to state that individuals are now more comfortable seeking to undergo not only ... calf and cheek reduction. The Los Angeles area medical group, Beverly Hills Physicians (BHP) ...
(Date:6/24/2016)... Fla. (PRWEB) , ... June 24, 2016 , ... Global ... Trend magazine’s 2016 Legal Elite. The attorneys chosen by their peers for this recognition ... Florida. , Seven Greenberg Traurig Shareholders received special honors as members of this year’s ...
(Date:6/24/2016)... ... June 24, 2016 , ... EB Medicine presented ... in Emergency Medicine conference in Ponte Vedra Beach, FL. The awards honor the ... Emergency Medicine Practice and Pediatric Emergency Medicine Practice. , “With this award, ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... Venture ... Golf Classic Tournament held on June 20th at the Woodmont Country Club at ... Luke’s Wings, an organization dedicated to helping service members that have been wounded in ...
(Date:6/24/2016)... ... June 24, 2016 , ... Southern Illinois ... are co-chairs for the Illinois State Dental Society (ISDS) Foundation’s Mission of Mercy ... Gateway Convention Center in Collinsville. , They expect to treat approximately ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... 23, 2016  Guerbet announced today that it has ... Horizon Award . One of 12 suppliers ... for its support of Premier members through exceptional local ... and commitment to lower costs. ... of our outstanding customer service from Premier," says ...
(Date:6/23/2016)... -- The Biotechnology industry might still be ... opportunities to investors. Stock-Callers.com assesses the recent performances of ... XON ), Vertex Pharmaceuticals Inc. (NASDAQ: ... ), and Regeneron Pharmaceuticals Inc. (NASDAQ: REGN ... complimentary trade alerts at: http://stock-callers.com/registration ...
(Date:6/23/2016)... Research and Markets has announced the addition ... New Global Agenda " report to their offering. ... Europe - the 2016 edition is a ... identifies the driving factors coming into play which will influence ... and in the future. It provides a wealth of knowledge ...
Breaking Medicine Technology: