The FDA estimates that two million patients in the U.S. start taking warfarin every year and it has been prescribed to patients for more than 50 years. Warfarin can provide enormous benefits, but the safe and effective dose varies greatly among patients. It is the second most common drug, after insulin, implicated in emergency room visits for adverse drug events, especially bleeding complications.
"Warfarin's effectiveness is widely known within the medical community, but it is underutilized because of concerns about the risk of bleeding complications," said AMA Board Member and cardiovascular disease specialist James Rohack, MD.
In August, the FDA changed the official labeling of warfarin to inform practitioners that genetic testing may help providers improve the initial dosing for individual patients.
"Studies show that genetic factors explain why 40 percent of patients taking warfarin are more sensitive to the drug and require a smaller dose," said Dr. Rohack. "Genetic testing can identify patients at high risk for bleeding complications when warfarin is started, and allow the physician to use smaller doses to reduce the initial bleeding risk."
"The brochure outlines the science behind genetic testing for warfarin dosing so physicians can incorporate this form of personalized health care into their practices," said Raymond Woosley, MD, PhD, President and CEO, C-Path. "The FDA is to be commended for its work to update the label and help inform the medical community of this modern scientific advancement that can improve a commonly prescribed medicine."