According to the Annals of Pharmacotherapy, 7% of Medication Errors are Caused by Blood Thinners. There are two types of blood thinners: anticoagulants and antiplatelet drugs. Anticoagulants work to prolong the amount of time that it takes for a person’s blood to clot. Antiplatelet drugs are used to prevent a person’s platelets from grouping, which result in a blood clot. Blood thinners are used to prevent a blood clot which can result in a heart attack or stroke.