Harvard Heart Letter
Preventing blood clots: Is warfarin still right for you?
Using warfarin effectively is challenging—perhaps even more so than doctors have realized. For more than 60 years, warfarin has been a mainstay for people with atrial fibrillation. Used properly, warfarin may prevent as many as 60% of strokes related to this common heart rhythm disorder each year. But warfarin is notoriously tricky to manage because blood levels have to be kept within a narrow range to avoid side effects such as