Discovered in 1916, Heparin is among the oldest drugs now in widespread clinical use. It gets its name from 'hepar', which means "liver" in Greek. It was given this name because it was isolated from canine liver cells. Today, you can even find a heterogeneous mixture of heparin called unfractionated heparin.
What Is Heparin?
Heparin is a family of medication used to reduce the ability of your body to form blood clots. There are two subtypes of heparins available today, which include low-molecular heparin and unfractionated heparin. There are two basic purposes of heparin: it is used as prophylactic dose against venous thromboembolic disease and also used as full anticoagulation for treatment of thromboembolic disease (it is given in therapeutic dose in this case).
Unfractionated heparin (UFH) is the outcome of a heterogeneous mixture of linear polysaccharide chains. These chains contain variable biological activity and molecular weight. It has been used for prevention of pulmonary embolism and deep venous thrombosis since the mid-1980s. In several European countries, there are different compounds of UFH that are considered effective in treating venous thromboembolism.
How Does Unfractionated Heparin Work?
When an injury results in bleeding, your brain sends out signals to develop a clot at the wound site. The clot breaks down and disappears as your wound heals. Sometimes, you develop a condition that causes an imbalance between the formation and breakdown of clot. This is when your doctor gives you anticoagulant medicines. By taking unfractionated heparin, you will stop your body from producing certain proteins required for blood clotting.
How Effective Is It?
Unfractionated heparin is a good choice for the treatment of deep vein thrombosis. It does not allow your body to produce protein that leads to the formation of new blood cloths. At the same time, it keeps existing blood clots from getting larger. It lets the normal body systems to take control and dissolve the clots. By keeping an existing blood clot from getting larger, heparin successfully reduces the risk of developing pulmonary embolism.
What Are the Side Effects?
Like other drugs, there are certain side effects associated with the use of unfractionated heparin. As it prevents blood clotting, there will always be a risk of having serious bleeding inside your body. Your doctor will keep you under observation while administering heparin. They will take steps as soon as they notice signs of bleeding or other problems.
Your doctor will give it to you through an IV, which is mainly because it can be turned off quickly when given intravenously. While your doctor will also ask for specific blood tests, you may still end up developing certain side effects, including irritation, pain, and bruising.
Unfractionated vs. Low Molecular Weight Heparins
As mentioned already, heparin is available in two different subtypes. Depending on your unique circumstances, your doctor will either opt for unfractionated heparin or choose to go with low molecular weight heparin.
Unfractionated Heparin
Mainly obtained from porcine intestine, it is mostly used for the treatment and prevention of thrombosis. It consists of a mixture of sulphated glucosaminoglycans of different molecular weights and size. With a change in the molecular weight and size, the anticoagulant effects and pharmacological properties will change as well. Administered parenterally, it binds to macrophages, platelet, plasma proteins, and endothelial cells to produce variable anticoagulant response. It also works by inactivating several coagulation enzymes, including Factors IIa, XIIa, Xia, IXa, and Xa.
Low Molecular Weight Heparins
It is obtained from UFH by depolymerization, and each of these products has specific molecular weight distribution. Due to specific weight distribution, it is easy to determine the duration of action. It is another reason why one LMWH product cannot be substituted for a different one. It is widely available today and is used as dalteparin, enoxaparin, certoparin, tinzaparin, nadroparin, ardeparin, reviparin, bemiparin, and parnaparin.
Unlike unfractionated heparin, it is given subcutaneously to prevent VTE. It works in the same way as UFH – it binds itself to AT50 and inactivates coagulation enzymes. However, it has a relatively lower affinity when it comes to binding to proteins. LMWHs produce fewer side effects, and that is the reason why most doctors rely on these types of heparin as compared to unfractionated heparin.