What does anticoagulant mean?
An anticoagulant is any substance that prevents or slows the coagulation of blood, thereby reducing the formation of harmful clots inside blood vessels. In medicine, anticoagulants are among the most widely prescribed classes of drugs: agents such as warfarin, heparin, and the newer direct oral anticoagulants are used to treat and prevent deep vein thrombosis, pulmonary embolism, and stroke, particularly in patients with atrial fibrillation or those recovering from major surgery. The term is chiefly clinical in register, though the looser phrase 'blood thinner' is common in everyday conversation despite being scientifically inaccurate, since these drugs alter clotting chemistry rather than the viscosity of blood itself. Derived from Latin roots meaning 'against' and 'to curdle', the word entered English in the early twentieth century alongside the development of modern haematology. Anticoagulants require careful dosing and monitoring, as excessive effect can cause dangerous bleeding.
nounA substance that prevents or delays the clotting (coagulation) of blood, used medically to treat or prevent conditions such as deep vein thrombosis, pulmonary embolism, and stroke.
- A drug or substance administered to prevent blood from clotting, especially in the treatment or prevention of thrombosis and embolism.
"Patients with atrial fibrillation are often prescribed an anticoagulant to reduce their risk of stroke."
"After her hip replacement surgery, she was given an anticoagulant to prevent dangerous clots from forming."
"Heparin is a fast-acting anticoagulant commonly used in hospitals during dialysis and cardiac procedures."
Standard regular plural, used when referring to multiple agents or the class of drugs as a whole.
"Several newer anticoagulants have been approved in the past decade as alternatives to warfarin."
Warfarin, one of the most widely used anticoagulants, began life as rat poison before doctors realised its power to keep human blood flowing too.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of anticoagulant
The word anticoagulant combines the prefix 'anti-', from Greek via Latin, meaning 'against', with 'coagulant', derived from the Latin verb 'coagulare', meaning 'to curdle' or 'to cause to clot', itself rooted in 'coagulum', a curdled mass. The term emerged in English in the early twentieth century, coinciding with the discovery and clinical development of the first effective anticoagulant drugs such as heparin in the 1910s–1920s and warfarin in the 1940s. It shares its Latin root with related medical terms including 'coagulate' and 'coagulation'.
How anticoagulant is actually used
The word is formal and clinical, appearing mainly in medical, pharmaceutical, and scientific contexts; in everyday speech people more often say 'blood thinner', though this is technically imprecise since anticoagulants do not actually thin the blood. The plural 'anticoagulants' is standard when referring to different drugs of this class.
Easily confused with anticoagulant
An anticoagulant interferes with the clotting cascade of proteins in the blood, whereas an antiplatelet drug such as aspirin prevents platelets from clumping together — both reduce clotting but by different mechanisms.
An anticoagulant prevents new clots from forming, while a thrombolytic actively dissolves clots that have already formed.