Antikoagulancii

Antikoagulancii are medicines that inhibit blood coagulation and thereby reduce the formation of clots. They do not dissolve existing clots but help prevent their growth or new clots in high-risk situations. They are used to prevent stroke in atrial fibrillation, treat and prevent venous thromboembolism, and reduce clotting risk in certain cardiac conditions and after some surgeries.

There are several main classes of antikoagulancii. Vitamin K antagonists, such as warfarin, work by inhibiting the synthesis of vitamin K–dependent clotting factors, requiring regular blood tests (INR) to monitor dosing and adjustments for diet and drug interactions. Heparins, including unfractionated heparin and low-molecular-weight heparins, enhance the action of antithrombin and are often used in hospital settings for rapid effect; monitoring commonly uses the aPTT for unfractionated heparin. Direct oral anticoagulants (DOACs) provide more predictable effects and include direct thrombin inhibitors (dabigatran) and direct factor Xa inhibitors (rivaroxaban, apixaban, edoxaban). DOACs typically do not require routine laboratory monitoring but require attention to renal function and drug interactions.

Indications cover nonvalvular atrial fibrillation, venous thromboembolism prophylaxis and treatment, and certain postoperative settings. DOACs are generally preferred for many patients, while vitamin K antagonists remain important when DOACs are contraindicated, such as in mechanical heart valves. Safety considerations include bleeding risk, drug and dietary interactions, and special considerations in pregnancy and kidney or liver disease.

Reversal and management of overdose depend on the agent: vitamin K and fresh frozen plasma for warfarin; protamine sulfate for heparins; idarucizumab for dabigatran; andexanet alfa for factor Xa inhibitors; in some cases, PCC may be used.