The purpose of this study is to determine the importance of genetic differences on
individuals' response to warfarin in a group of healthy subjects. Warfarin is also known by
the "trade name" Coumadin and is in a class of medications called anticoagulants or "blood
thinners." Warfarin works by reducing the blood's ability to make clots. It is used to stop
blood clots from forming or growing larger in your blood and blood vessels. Warfarin is
prescribed for many conditions, including for people with certain types of irregular
heartbeat, people with replacement or mechanical heart valves, people who have suffered a
heart attack, people who have had orthopedic surgery, or who have a history of having blood
clots. Warfarin is used to prevent or treat deep vein thrombosis (swelling and blood clot in
a vein), pulmonary embolism (a blood clot in the lung), and strokes (a blood clot in the
brain). Researchers have found that certain genes may affect how a person's body will break
down or react to warfarin. If genetic information can help doctors better determine the best
dose of warfarin before it is first given, this may help the doctors get patients to the
correct levels of blood thinning and thereby reduce the risk of bleeding or the risk of
developing a blood clot. The expectation of this study is that this information will
ultimately improve warfarin therapy while lessening the risks associated with dosing errors.
This study is considered investigational because the subjects are healthy and not being
prescribed warfarin for clinical care.