Heparin, sometimes referred to as “eparina,” is a medication widely used to prevent and treat blood clots. It is a naturally occurring substance found within the body, specifically produced by cells like basophils and mast cells. This medication plays a significant role in modern medicine due to its ability to prevent the formation of new blood clots and stop existing ones from growing larger. Its properties make it a commonly used anticoagulant, often referred to as a “blood thinner,” although it does not truly thin the blood.
How Heparin Works
Heparin exerts its anticoagulant effect by enhancing the activity of a natural protein in the blood called antithrombin (AT). Antithrombin works to inactivate several key enzymes involved in the blood clotting process. When heparin binds to antithrombin, it causes a change in antithrombin’s structure, which significantly increases its ability to inhibit these clotting factors.
This enhanced activity prevents the coagulation cascade, the complex series of steps that lead to blood clot formation. While heparin is highly effective at preventing new clots and stopping existing ones from enlarging, it does not dissolve clots that have already formed. Instead, it allows the body’s natural processes to gradually break down existing clots over time.
Medical Applications of Heparin
Heparin is commonly prescribed for the treatment and prevention of deep vein thrombosis (DVT), which are blood clots forming in deep veins, often in the legs, and pulmonary embolism (PE), a serious condition where a clot travels to the lungs. Heparin helps to prevent the extension of these clots and reduces the risk of recurrence.
Heparin is also used in various other medical contexts:
During certain surgical procedures, such as cardiac surgery and angioplasty, to prevent clotting.
In kidney dialysis, to prevent blood from clotting within the machine tubing.
It plays a role in managing specific heart conditions, including unstable angina and certain types of heart attacks (myocardial infarction), by preventing further clot formation in the heart’s blood vessels.
Heparin also helps maintain the patency of medical devices like catheters, preventing blockages.
Important Considerations for Heparin Use
Heparin is typically administered through injection, either intravenously (directly into a vein) or subcutaneously (under the skin). Due to its potent effect on blood clotting, careful monitoring is necessary to ensure the medication is effective without causing undue risk.
A common laboratory test used to monitor heparin therapy is the activated partial thromboplastin time (aPTT), which measures how long it takes for blood to clot. Adjustments to the heparin dose are made based on these test results to maintain a therapeutic range, typically between 60-80 seconds, though this can vary by laboratory.
The most significant potential side effect of heparin is bleeding, which can range from minor bruising to more serious internal hemorrhages. Patients are closely observed for signs of bleeding. A less common, but serious, consideration is heparin-induced thrombocytopenia (HIT), a condition where the body’s platelet count drops significantly, which can paradoxically increase the risk of new clots. Heparin use always requires close medical supervision.