What are Heparin and Warfarin?

Both of these drugs are blood thinners used for the treatment and prevention of thrombosis or blood clots. A blood clot causes blockage in the arteries that prevent blood and oxygen supply from traveling to other organs of the body. The tissues that do not get enough blood supply due to clots will die and can lead to serious illnesses such as myocardial infarction or stroke. 

Blood thinners are important to keep the blood running smoothly through the arteries and veins. They are unable to tear down existing clots but can prevent small clots from getting bigger. 

How Do Anticoagulants Work?

Anticoagulants interfere with the clotting factors or proteins in the liver called “cofactors” and delay the clotting process. The formation of these cofactors is controlled by vitamin K. Warfarin helps by hindering Vitamin K to work properly, while Heparin blocks cofactors such as “Thrombin “ and “Fibrin” from functioning properly, thus preventing blood from clotting. 

Heparin 

This anticoagulant is usually prepared in liquid form and commonly administered intravenously. It is a fast-acting blood thinner and works within minutes after administration. It should be given at a correct dose and the patient receiving it has to be monitored and tested every day.

Heparin is under the “Indirect Thrombin Inhibitors” class of blood thinners—a family of coagulants that directly delay clotting by inhibiting thrombin and the production of fibrin, improving the production of antithrombin III which is a protein that prevents blood clots. 

Heparin also affects the intrinsic pathway of coagulation by activating Toserine Protease Inhibitor through binding and deactivating the Factors Xa and Thrombin, proteins needed for the clotting process. 

Common Side Effects of Heparin

• The patient easily gets bruises, and bleeding takes longer to suppress
• Frequent gum bleeding or nose bleeds
• Pink or dark-brown-colored urine
• A patient may also experience severe allergic reactions 
• Heparin-Induced Thrombocytopenia or commonly known as HIT

Long-term usage or high doses of Heparin can cause osteoporosis and erratic changes with a patient’s aPTT. An antidote for heparin interaction is Protamine Sulfate. 

Warfarin

This coagulant is usually taken in oral form. It is commonly used to treat blood clots that could lead to cardiac problems such as MI or stroke. It has a slower onset and takes at least 3-5 days to take effect but stays in the system longer, mostly for days. 

Warfarin is under the coagulant family of Vitamin K antagonists. It works by blocking an essential enzyme that activates Vitamin K, which is the Vitamin K Epoxide Reductase Complex 1 or VKRC1. It extensively binds to plasma proteins and commonly works on an extensive coagulation pathway that gets activated by outside trauma. 

Warfarin can cross placental barriers and causes fetal anticoagulation. It could cause abortion and stillbirth and should be used with precaution for pregnant women. It has greater effects on the fetus than on the mother. 

With Warfarin, the prothrombin time and the Internationalize ratio should be monitored. The antidote for warfarin intoxication is Vitamin K. 

Common Side Effects of Warfarin

• Patient coughing up blood
• Nausea and vomiting
• Tarry black stools and brown-colored urine
• Purple toe syndrome
• Elevated liver enzymes