Anticoagulants are drugs used to prevent or delay blood coagulation and clotting. They are used in anticoagulant therapy to treat or prevent disorders such as pulmonary embolisms caused by vascular thrombosis, as well as for infarctions. The most well-known anticoagulant is heparin, but sodium citrate and warfarin sodium are also used.
After given anticoagulants, patients are watched carefully to assure no adverse effects from the therapy, the most common of which is bleeding. Laboratory tests are conducted to check the levels of the drug and the patient is assessed daily for signs or symptoms of bleeding.
Anticoagulants must be avoided for patients who have had surgery or where surgery is planned. A patient given surgery while taking anti-coagulants is almost certain to bleed to death either during or after surgery.