Anticoagulants are used to treat and prevent blood clots
Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where they help keep the bite area unclotted long enough for the animal to obtain some blood. As a class of medications, anticoagulants are used in therapy for thrombotic disorders. Oral anticoagulants (OACs) are taken by many people in pill or tablet form, and various intravenous anticoagulant dosage forms are used in hospitals. Some anticoagulants are used in medical equipment, such as sample tubes, blood transfusion bags, heart-lung machines, and dialysis equipment. One of the first anticoagulant, warfarin, was initially approved as a rodenticides.
The use of anticoagulants is a decision based upon the risks and benefits of anticoagulation. The biggest risk of anticoagulation therapy is the increased risk of bleeding. In otherwise healthy people, the increased risk of bleeding is minimal, but those who have had recent surgery, cerebral aneurysms, and other conditions may have too great of risk of bleeding. Generally, the benefit of anticoagulation is prevention of or reduction of progression of a thromboembolic disease. The most serious and common adverse side effect associated with anticoagulant are increased risk of bleeding, both nonmajor and major bleeding events. Risk of bleeding is dependent on the class of anticoagulant agent used, patient's age, and pre-existing health conditions. Warfarin has an estimated Incidence of bleeding of 15-20% per year and life-threatening bleeding rate of 1-3% per year.
Onhemorrhagic adverse events are less common than hemorrhagic adverse events but should still be monitored closely. Nonhemorrhagic adverse events of warfarin include skin necrosis, limb gangrene, and purple toe syndrome. Skin necrosis and limb gangrene are most commonly observed on the third to eighth day of therapy. The exact pathogenesis of skin necrosis and limb gangrene are not completely understood but are believed to be associated with warfarin's effect on inhibiting production of protein C and protein S. Purple toe syndrome typically develops three to eight weeks after initiation of warfarin therapy. Other adverse effects of warfarin are associated with depletion of vitamin K, which can lead to inhibition of G1a proteins and growth arrest-specific gene 6, which can lead to increased risk of arterial calcification and heart valve, especially if too much Vitamin D is present. Warfarin's interference of G1a proteins have also been linked to abnormalities in fetal bone development in mothers who were treated with warfarin during pregnancy. Long-term warfarin and heparin usage have also been linked to osteoporosis.
A number of anticoagulants are available. The traditional ones (warfarin, other coumarins and heparins) are in widespread use. Since the 2000s a number of agents have been introduced that are collectively referred to as directly acting oral anticoagulants (DOACs), novel oral anticoagulants (NOACs), or non-vitamin K antagonist oral anticoagulants. These agents include direct thrombin inhibitor (dabigatran) and factor Xa inhibitor (rivaroxaban, apixaban, betrixaban and edoxaban) and they have been shown to be as good or possibly better than the coumarins with less serious side effects. The newer anticoagulants (NOACs/DOACs), are more expensive than the traditional ones and should be used with care in patients with kidney problems.
Journal of Pharmacy Practice and Education,