Also known as: blood thinners, DOACs, vitamin K antagonists
Medicines that slow the clotting cascade to prevent and treat clots in veins and the heart: strokes in atrial fibrillation, deep vein thrombosis and pulmonary embolism.
Direct oral anticoagulants block a single clotting enzyme: factor Xa (apixaban, rivaroxaban, edoxaban) or thrombin (dabigatran), with a predictable effect that needs no blood-level monitoring. Warfarin instead starves the liver of usable vitamin K, so factors II, VII, IX and X are made in inactive form; its effect builds over days and varies with diet and other drugs, so the INR test tunes the dose. Heparins, given by injection, activate antithrombin and are used in hospital and pregnancy.
Avoid NSAIDs and aspirin unless specifically advised
Doses adjusted for kidney function, weight and age
Stopped before surgery on a plan; missed DOAC doses lose protection within a day
Warfarin needs a steady vitamin K intake and INR checks
Class warnings
Bleeding is the shared major hazard; signs such as blood in urine or stools, prolonged nosebleeds, coughing or vomiting blood, severe headache or unusual bruising need urgent assessment. Interacting drugs, kidney impairment and older age raise the risk. UK
Warfarin needs regular INR monitoring and is affected by diet, alcohol, illness and many medicines; DOACs are dosed by kidney function, weight and age and need periodic renal function checks. UK
Therapeutic duplication. Two anticoagulants together (for example warfarin with a DOAC outside a supervised switch) multiply bleeding risk and are avoided. UK
Educational content. A drug class page describes what a family of medicines has in common. Individual medicines differ in dose, licensing and interactions; treatment choices belong to a prescriber.
