Definition:
Anticoagulants are medications that inhibit blood clot formation, thereby reducing the risk of thromboembolic events such as deep vein thrombosis, pulmonary embolism, and stroke.
They are essential in preventing abnormal clotting in various medical conditions.
Mechanism of Action:
Vitamin K Antagonists:
Drugs like Warfarin and Anisindione inhibit the enzyme vitamin K epoxide reductase, decreasing the regeneration of active vitamin K.
This impairs the synthesis of vitamin K-dependent clotting factors (II, VII, IX, and X), reducing the blood's ability to form clots.
Antiplatelet Agents:
Clopidogrel inhibits platelet aggregation by blocking the P2Y₁₂ ADP receptor on platelets, preventing them from clumping together to form clots.
Common Anticoagulant Drugs:
Vitamin K Antagonists:
Warfarin
Anisindione
Antiplatelet Agents:
Clopidogrel
Uses:
Preventing and treating thromboembolic disorders (e.g., deep vein thrombosis, pulmonary embolism)
Stroke prevention in patients with atrial fibrillation
Prophylaxis in individuals with mechanical heart valves
Reducing the risk of heart attacks and strokes in patients with coronary artery disease
Side Effects:
Vitamin K Antagonists:
Increased risk of bleeding
Teratogenic effects (contraindicated in pregnancy)
Numerous drug and food interactions affecting vitamin K levels
Antiplatelet Agents:
Increased risk of bleeding
Gastrointestinal discomfort
Rarely, thrombotic thrombocytopenic purpura (TTP)