oralantikoagulantia

Oralantikoagulantia (oral anticoagulants) are medications taken by mouth that reduce the blood’s ability to form clots. They are used to prevent and treat thromboembolic disorders by interfering with the coagulation cascade, thereby lowering the risk of abnormal clot formation in arteries or veins.

The two main classes are vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs). VKAs, such as warfarin, acenocoumarol, and phenprocoumon, inhibit vitamin K–dependent clotting factors. DOACs include dabigatran (a direct thrombin inhibitor) and factor Xa inhibitors such as rivaroxaban, apixaban, and edoxaban. In general, VKAs require regular laboratory monitoring, whereas DOACs are prescribed with fixed dosing and less routine monitoring.

Indications commonly include prevention of stroke in nonvalvular atrial fibrillation, treatment and prevention of venous thromboembolism (deep vein thrombosis and pulmonary embolism), and prophylaxis after major orthopedic surgery. Mechanical heart valves and certain rheumatic valve diseases are typically managed with VKAs; DOACs are usually avoided in these settings. Choice of agent depends on factors such as renal function, age, drug interactions, and patient adherence.

Monitoring and safety considerations vary by class. VKAs require periodic international normalized ratio (INR) testing to maintain a target range. DOACs rely less on monitoring but depend on renal function and may interact with other drugs. Reversal strategies differ: vitamin K reverses VKAs; specific antidotes exist for some DOACs (e.g., idarucizumab for dabigatran and andexanet alfa for factor Xa inhibitors), with additional agents used in bleeding scenarios as needed.

Common adverse effects include increased bleeding risk; careful patient selection, dosing, and monitoring are essential to balance efficacy and safety.