The Threat of Common Anticoagulants

Warfarin and Heparin are two common anticoagulants used to prevent thrombosis. They are both very effective at what they do, but come with some serious risks. Warfarin (market brand Coumadin) is a natural chemical found in plants that was originally marketed as a rat pesticide. Research uncovered Warfarin’s relatively safe and effective use as an anticoagulant not long after. If used at a safe dosage, Warfarin can prevent both thrombosis and embolism. The way Warfarin works is by inhibiting Vitamin K epoxide reducatase, therefore diminishing the amount of Vitamin K available in tissues and inhibiting the Vitamin K synthesis of many calcium dependent and regulator factors. This inhibition prevents the carboxylation activity necessary for coagulation factors to bind to blood vessel surfaces. The primary side effect of this effective clot-preventing drug is hemorrhage. Although the risk for hemorrhage is small, it is definite, which means that Warfarin derivatives should only be used if absolutely necessary.

Heparin (market brand Calciparine or Hep-lock) is an injectable anticoagulant, which makes it a much faster acting prevention for thrombosis than Warfarin. Heparin is derived from the mucosal tissues of slaughtered meat such as pigs and cows. It is a naturally occurring anticoagulant that is produced in basophils and mast cells. Heparin prevents clot formation and extension by binding to antithrombin 3 inhibitor, which then inactivates the body’s blood clotting response. The major side effect of this drug is known as Heparin-Induced Thrombocytopenia Syndrome, or HITS. This side effect makes the body’s blood platelets an immunological target, leading to the degradation of platelets.

Due to the considerable effectiveness of these two drugs, they are some of the most commonly used anticoagulants. Warfarin is typically administered as a prescription drug to patients who have already formed a blood clot. Because of its strong side effects, patients are required to submit a blood sample as often as once a day to ensure a proper dosage level is maintained. Heparin is restricted primarily to hospital use because it must be administered as a continuous infusion or as frequently as every half hour. Both of these treatments are very effective at preventing blood clots, but with side effects as severe as these, any patient considering starting Warfarin or Heparin should be cautious!