<unk>  is used to decrease the tendency for thrombosis, or as secondary prophylaxis (prevention of further episodes) in those individuals who have already formed a blood clot (thrombus).<unk>  treatment can help prevent formation of future blood clots and help reduce the risk of embolism (migration of a thrombus to a spot where it blocks blood supply to a vital organ).<unk>  is best suited for anticoagulation (clot formation inhibition) in areas of slowly running blood (such as in veins and the pooled blood behind artificial and natural valves), and in blood pooled in dysfunctional cardiac atria. Thus, common clinical indications for<unk>  use are atrial fibrillation, the presence of artificial heart valves, deep venous thrombosis, and pulmonary embolism (where the embolized clots first form in veins).<unk>  is also used in antiphospholipid syndrome. It has been used occasionally after heart attacks (myocardial infarctions), but is far less effective at preventing new thromboses in coronary arteries. Prevention of clotting in arteries is usually undertaken with antiplatelet drugs, which act by a different mechanism from<unk>  (which normally has no effect on platelet function). It can be used to treat people following ischemic strokes due to atrial fibrillation, though direct oral anticoagulants (DOACs) may offer greater benefits. Dosing Dosing of<unk>  is complicated because it is known to interact with many commonly used medications and certain foods. These interactions may enhance or reduce<unk> 's anticoagulation effect. To optimize the therapeutic effect without risking dangerous side effects such as bleeding, close monitoring of the degree of anticoagulation is required by a blood test measuring an INR. During the initial stage of treatment, INR is checked daily; intervals between tests can be lengthened if the patient manages stable therapeutic INR levels on an unchanged<unk>  dose. Newer point-of-care testing is available and has increased the ease of INR testing in the outpatient setting. Instead of a blood draw, the point of care test involves a simple finger prick. Maintenance dose Vitamin K1-warfarin interaction effect. When<unk>  levels are high, people have more risk of bleeding. Conversely, lower levels of<unk>  lead to increased risk of blood clots. There is a narrow range where the benefits of<unk>  are greater than the risks, its therapeutic window. Certain drugs, herbal medicines, and foods can interact with<unk> , increasing or decreasing a previously stable<unk>  level. Recommendations by many national bodies, including the American College of Chest Physicians, have been distilled to help manage dose adjustments. The maintenance dose of<unk>  can fluctuate significantly depending on the amount of vitamin K1 in the diet. Keeping vitamin K1 intake at a stable level can prevent these fluctuations. Leafy green vegetables tend to contain higher amounts of vitamin K1. Green parts of members of the family Apiaceae, such as parsley, cilantro, and dill are extremely rich sources of vitamin K; cruciferous vegetables such as cabbage and broccoli, as well as the darker varieties of lettuces and other leafy greens, are also relatively high in vitamin K1. Green vegetables such as peas and green beans do not have such high amounts of vitamin K1 as leafy greens. Certain vegetable oils have high amounts of vitamin K1. Foods low in vitamin K1 include roots, bulbs, tubers, and most fruits and fruit juices. Cereals, grains, and other milled products are also low in vitamin K1. Self-testing Anticoagulation with<unk>  can also be monitored by patients at home. International guidelines on home testing were published in 2005. The guidelines stated: The consensus agrees that patient self-testing and patient self-management are effective methods of monitoring oral anticoagulation therapy, providing outcomes at least as good as, and possibly better than, those achieved with an anticoagulation clinic. All patients must be appropriately selected and trained. Currently available self-testing/self-management devices give INR results that are comparable with those obtained in laboratory testing. A 2006 systematic review and meta-analysis of 14 randomized trials showed home testing led to a reduced incidence of complications (thrombosis and major bleeding), and improved the time in the therapeutic range. Alternative anticoagulants In some countries, other coumarins are used instead of<unk> , such as acenocoumarol and phenprocoumon. These have a shorter (acenocoumarol) or longer (phenprocoumon) half-life, and are not completely interchangeable with<unk> . Several types of anticoagulant drugs offering the efficacy of<unk>  without a need for monitoring, such as dabigatran, apixaban, edoxaban, and rivaroxaban, have been approved in a number of countries for classical<unk>  uses. Complementing these drugs are reversal agents available for dabigatran (idarucizumab), and for apixaban, and rivaroxaban (andexanet alfa). Andexanet alfa is suggested for edoxaban, but use of it is considered off label due to limited evidence. A reversal agent for dabigatran, apixaban, edoxaban, and rivaroxaban is in development (ciraparantag).
Warfarin
Palladin
Clopidogrel
Ticlopidine
Apixaban
Ticagrelor
Heparin
Dabigatran