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Brief about Anticoagulant Examples – Definition, Classification, & Side Effect

Anticoagulant drugs:

Anticoagulants or blood thinners are chemicals that reduce or prevent coagulation of blood and increases the clotting time. These chemicals are naturally present in blood-eating animals like mosquitoes and leeches that allow the bite area to be un-clotted to suck blood to normalize the Blood Pressure.

In diseases like Coronary artery disease, Atrial fibrillation, and Ischemic stroke, Deep vein thrombosis, Pulmonary embolism, Restenosis from stents, Hypercoagulable conditions like Factor V Leiden, Myocardial infarction, etc anticoagulants help in the prevention of formation of clots and restrict its growth.

Anticoagulant definition

Anticoagulants, often known as blood thinners, are chemical agents that prevent or diminish blood coagulation, resulting in a longer clotting time. Some of them are found naturally in blood-feeding animals like leeches and mosquitoes, where they aid in keeping the bite area unclotted long enough for the animal to get some blood.

Anticoagulants are a type of drug used to treat thrombotic diseases. Many people take oral anticoagulants (OACs) in pill or tablet form, while hospitals utilize a variety of intravenous anticoagulant dose forms.

Anticoagulants examples:

These medications are also known as “blood thinners.” Your blood isn’t actually thinned by them. They can, however, aid in the prevention of clot formation.

  • warfarin (Coumadin)

Is aspirin an anticoagulant?

Blood thinners come in a variety of forms: Anticoagulants like heparin and warfarin (commonly known as Coumadin) slow down your body’s clotting mechanism. Aspirin and clopidogrel are antiplatelet medications that prevent platelets from clumping together and forming a clot.

Anticoagulant side effects:

Because anticoagulants prolong the time it takes for blood clots to form, heavy bleeding (hemorrhage) is a possible side effect.

Excessive bleeding:

  1. Urine that contains blood
  2. Severe bruise from passing blood when pooping or having black poo
  3. Nosebleeds that linger a long time (lasting longer than 10 minutes)
  4. Sudden severe back pain after vomiting or spitting up blood
  5. Women may experience trouble breathing or chest pain, as well as heavy or increased flow during their periods or any other vaginal bleeding.

Check the leaflet that came with your medicine for a complete list of potential side effects.

Other possible adverse effects include:

  • Diarrhea or Constipation
  • Feeling and Being Sick
  • Indigestion
  • Dizziness
  • Headaches
  • Rashes
  • Itchy Skin
  • Hair Loss
  • Jaundice (Yellowing of the Eyes And The Skin, Although This May Be Less Obvious On Black Or Brown Skin)

Anticoagulant Classification

Coumarins and indandiones, factor Xa inhibitors, heparins, and direct thrombin inhibitors are the four primary types of anticoagulants.

Novel oral anticoagulant or Non Vitamin K antagonist oral anticoagulant Example (NOACs)

They inhibit the formation of clots but are not Vitamin K antagonists. They include rivaroxaban, apixaban, dabigatran etc. They have comparatively shorter half-lives and rapid action than warfarin and are a lot more expensive than them.

Coumarins (vitamin K antagonists)

the most important medicine in this class is warfarin. It takes 42 to 72 hours for the development of anticoagulation. Other medicines belonging to this class include phenindione, phenprocoumon, acenocoumarol, and tormenting.

Heparin and derivative substances

Heparin is made from the intestines of pig. It acts by activating antithrombin III, which in turn prevents thrombin from clotting blood. Heparin is used both in-vivo and in-vitro for blood clotting.

Low molecular weight heparin

it is a more processed form of heparin and is frequently used since has fewer side effects and it does not require monitoring of APTT coagulation parameters.

Synthetic pentasaccharide inhibitors of factor Xa- Idraparinux, Fondaparinux 

Direct factor Xa inhibitors

Direct factor Xa inhibitor Example Apixaban, edoxaban, betrixaban, eribaxaban, letaxaban, darexaban, rivaroxaban etc.

Direct thrombin inhibitors

Direct thrombin inhibitors– ximelagatran, argatroban, lepirudin, hirudin, bivalirudin and dabigatran.

Antithrombin protein therapeutics– it is obtained from human plasma 

Other Anticoagulant types

Other types of anticoagulants- Batroxobin (from snake’s venom), Hementin (from Amazon leech Haementeria ghilianii), Vitamin E


  • Patients who are older may bleed more easily.
  • Patients with recent surgeries and cerebral aneurysms have a greater risk of bleeding


The information given in this write-up is purely for educating the reader. It is not meant to be a substitute for any advice from a medical expert.

Written by Dr. Ozair (CEO of SignSymptom.com) as physician writers are physicians who write creatively in fields outside their practice of medicine.

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