<unk> , sold under the brand name Coumadin among others, is a medication that is used as an anticoagulant (blood thinner). It is commonly used to prevent blood clots such as deep vein thrombosis and pulmonary embolism, and to prevent stroke in people who have atrial fibrillation, valvular heart disease or artificial heart valves. Less commonly it is used following ST-segment elevation myocardial infarction (STEMI) and orthopedic surgery. It is generally taken by mouth, but may also be used by injection into a vein. The common side effect is bleeding. Less common side effects may include areas of tissue damage and purple toes syndrome. Use is not recommended during pregnancy. It is recommended that the effects of<unk>  typically be monitored by checking prothrombin time (INR) every one to four weeks. Many other medications and dietary factors can interact with<unk> , either increasing or decreasing its effectiveness. The effects of<unk>  may be reversed with phytomenadione (vitamin K1), fresh frozen plasma, or prothrombin complex concentrate.<unk>  decreases blood clotting by blocking an enzyme called vitamin K epoxide reductase that reactivates vitamin K1. Without sufficient active vitamin K1, clotting factors II, VII, IX, and X have decreased clotting ability. The anticlotting protein C and protein S are also inhibited, but to a lesser degree. A few days are required for full effect to occur, and these effects can last for up to five days. Additionally, because the mechanism involves enzymes such as VKORC1, patients on<unk>  with polymorphisms of the enzymes may require adjustments in therapy to account if the genetic variant that they have is more readily inhibited by<unk> , thus requiring lower doses.<unk>  first came into large-scale commercial use in 1948 as a rat poison.<unk>  was formally approved for human use by the U.S. Food and Drug Administration (FDA) to treat blood clots in 1954. In 1955,<unk> 's reputation as a safe and acceptable treatment was bolstered when President Dwight D. Eisenhower received<unk>  following a massive and highly publicized heart attack. Eisenhower's illness kickstarted a transformation in medicine where coronary artery disease, arterial plaques, and ischemic strokes were treated and prevented by using blood thinners such as<unk> . It is on the World Health Organization's List of Essential Medicines.<unk>  is available as a generic medication. In 2019, it was the 50th most commonly prescribed medication in the United States, with more than 14million prescriptions.
Warfarin
Palladin
Clopidogrel
Ticlopidine
Apixaban
Ticagrelor
Heparin
Dabigatran