Apixaban (marketed as Eliquis) is an oral anticoagulant medication, commonly referred to as a blood thinner, prescribed to manage and prevent dangerous blood clots. Apixaban functions as a highly selective direct inhibitor of Factor Xa (FXa), a critical enzyme in the coagulation cascade. By blocking FXa activity, the drug disrupts the chain reaction that leads to the formation of thrombin and a stable fibrin clot. This targeted action reduces the blood’s ability to clot, lowering the risk of life-threatening events caused by unwanted clots.
Preventing Stroke in Non-Valvular Atrial Fibrillation
Non-valvular Atrial Fibrillation (AFib) is a common heart rhythm disorder characterized by a rapid, irregular quivering of the upper chambers of the heart. This abnormal rhythm prevents the atria from fully emptying, allowing blood to pool and form small clots inside the heart. If these clots travel through the bloodstream and lodge in an artery leading to the brain, they cause an ischemic stroke.
Apixaban is indicated to lower the risk of stroke and systemic embolism in individuals with non-valvular AFib. The non-valvular classification excludes AFib caused by moderate to severe mitral stenosis or a mechanical heart valve, which may require different anticoagulants. Clinical trials have demonstrated that apixaban is effective in this population.
The ARISTOTLE trial showed apixaban was superior to warfarin for preventing stroke or systemic embolism. Apixaban achieved this with a lower rate of major bleeding events, including intracranial bleeding. Its predictable profile allows for consistent clot prevention without the need for frequent blood monitoring, positioning apixaban as a preferred option for long-term stroke prevention in patients with non-valvular AFib.
Treating and Preventing Recurrence of Deep Vein Thrombosis and Pulmonary Embolism
Apixaban is used both to treat existing Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE), and to prevent their recurrence. DVT occurs when a blood clot forms in a deep vein, usually in the leg, causing pain and swelling. The primary danger is that a piece of the DVT can travel to the lungs, causing a PE, which is a serious blockage of the pulmonary arteries.
For the initial, acute treatment of DVT or PE, apixaban starts at a higher dose for the first seven days to rapidly address the existing clot burden. This regimen inhibits Factor Xa, stopping clot growth and allowing the body to begin resolving the blockage. Apixaban can often be initiated orally, avoiding the need for initial injectable anticoagulants, such as heparin or enoxaparin.
Following the acute phase, the dosage is reduced for ongoing treatment, typically lasting at least six months. After this duration, apixaban may be continued at a lower dose for long-term secondary prevention in patients with a high risk of recurrence. This extended regimen is indicated to keep new clots from forming, reducing the patient’s risk of experiencing another DVT or PE event.
Preventing Clots Following Major Orthopedic Surgery
Major orthopedic procedures, particularly total hip and total knee replacement surgery, carry a substantial risk for clot formation due to surgical trauma and prolonged immobility. Damage to blood vessels and reduced blood flow post-operation create a high-risk environment for developing DVT, which could progress to a PE. Apixaban is indicated for short-term, prophylactic use following these surgeries to mitigate this risk.
For prevention, the medication is administered at a low dose, with the first dose usually taken 12 to 24 hours after surgery once surgical bleeding is controlled. The duration of this preventative therapy depends on the procedure performed. Following a total hip replacement, apixaban is typically continued for approximately 35 days, reflecting the prolonged risk associated with this surgery.
For patients undergoing total knee replacement surgery, the recommended duration of prophylactic treatment is shorter, usually lasting around 12 to 14 days. This short-term usage protects the patient during the period of highest risk immediately post-operation and during initial recovery. Clinical data supported apixaban’s effectiveness in preventing venous thromboembolism with a favorable bleeding profile compared to alternative agents.