There are many people who need to take anticoagulation medications, most often warfarin to help prevent excess blood clotting. Warfarin is commonly prescribed for people with a variety of heart conditions, and there are other medical conditions that can warrant its use, or the use of drugs like heparin, which also needs close attention. The trouble with these medications is that getting blood levels of the medications accurate takes some work, and it’s easy to throw off levels by eating certain foods, when people get sick, or as a result of using other medications.