Warfarin

• You may know this drug as: Coumadin®, Jantoven®, Marevan®, Lawarin®, Waran®
• Why it's commonly used: Warfarin is prescribed to prevent blood clots in a variety of conditions, including irregular heartbeat, deep vein thrombosis, the presence of artificial heart valves, and, occasionally, after heart attacks.
• Effectiveness concerns: Sensitivity to warfarin usually varies greatly from person to person, and finding the correct personal dose for any individual is complicated. In finding that dose, the stakes are high – too much warfarin and a person may experience dangerous bouts of bleeding, too little and a person may suffer blood clots. The most serious problem related to warfarin sensitivity is excessive bleeding.
• What you can do: Given how complicated it is to find the correct warfarin dose for anyone, the process often begins with trial and error. Knowing your genetic results can improve on that guessing game and reduce the time it takes to find your correct dose.
• Did you know? Warfarin is prescribed about two million times a year in the United States. Nearly 1,000 serious warfarin-induced problems are reported each year – that's about three every day. Many more people experience episodes that are less serious but still require treatment.

The genetics of warfarin are complex, as are the challenges of personalized warfarin dosing. In analyzing your warfarin-related genetics, Navigenics looks at four places contained within three genes in your genetic code. We also provide a version of your warfarin genetic results that your doctor can use in a personal dosing calculator built for physicians by www.warfarindosing.org.