Anticoagulants and Their Mechanism of Action

Anticoagulants are part of the treatment of people with atrial fibrillation or a history of thrombosis, among others.
Anticoagulants and Their Mechanism of Action
Leonardo Biolatto

Written and verified by the doctor Leonardo Biolatto.

Last update: 27 May, 2022

Anticoagulants, as their name suggests, are drugs that prevent blood clotting. This is a normal physiological process that stops bleeding and keeps us from hemorrhaging under normal conditions.

However, the formation of a clot isn’t always to our benefit. Certain conditions increase the tendency to clot and lead to a risk of clogging a blood vessel and obstructing the flow.

Many conditions cause this state of hypercoagulability and these drugs are one of the basic pillars of treatment. Some examples are:

The coagulation process is complex. Furthermore, anticoagulants have various mechanisms of action within the human organism. Today’s article will explain everything you might want to know about them.

What are anticoagulants for?

As we mentioned above, anticoagulants either keep clots from forming or help them dissolve if they’ve already formed. Their main purpose is to prevent embolism and thrombosis.

A doctor massaging a leg.

The term “thrombosis” refers to a clot blocking a blood vessel. It can be a vein or an artery. The problem is that blood flow can’t continue and the tissue is damaged when this occurs. For example, this is what can happen in a myocardial infarction due to a blockage of the coronary arteries.

An embolism happens when a clot forms in any part of the body. However, it breaks off and obstructs a vessel elsewhere in the body in the end. Thus, pulmonary thromboembolism is one of the most typical conditions in this case. Such a clot usually forms in the legs and travels to the vessels of the lung. These are narrower so the clot obstructs them.

Anticoagulants help prevent these processes in people with a certain predisposition or a history of other episodes. For example, they’re essential in the treatment of atrial fibrillation. There’s a greater tendency for clots to form in this condition.

Check out these Recommendations for People on Anticoagulant Treatment

Types of anticoagulants

The mechanism of action of these drugs happens at different points of the clotting process. Let’s explain the most commonly used ones, heparins and oral anticoagulants, such as acenocoumarol, also known as Sintrom.

Firstly, know that vitamin K must be present for coagulation to take place. In the same way, a series of factors, called coagulation factors, must be active. Thrombin is one of the most important therapeutic targets.

Oral anticoagulants

These prevent the action of vitamin K and are the most commonly used for prolonged use; in atrial fibrillation and in people with prosthetic heart valves, for example.

What we must emphasize is these drugs require quite strict control. In addition, they can interact with many other drugs. This is why physicians should always be aware of these types of treatments.

A person holding two pills.


This drug inhibits thrombin, the factor we mentioned above. There are two main types of heparins: low molecular weight and unfractionated. The main difference between the two is the size of their molecules.

This is important because it determines how the drug is to be administered. Thus, low molecular weight heparins can be injected under the skin but unfractionated ones must be used intravenously.

These anticoagulants are used, among other things, when a person is bedridden for a long time. When they break a leg, for example. This is because immobilization stimulates clot formation.

Anticoagulants preserve lives

What we must remember is that anticoagulants are essential to prevent numerous conditions — such as heart attacks. They’re also quite useful in situations of immobilization.

However, they’re not simple drugs, so it’s important to consult your doctor if you have any doubts about taking them. This kind of specialist must monitor and follow the treatment to avoid unwanted complications.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.