Apixaban, marketed as Eliquis, is an oral anticoagulant medication. It reduces the likelihood of harmful blood clots forming in the body, managing conditions where clots pose a health risk. Apixaban provides a targeted approach to anticoagulation, distinguishing itself from older therapies.
Stroke Prevention in Atrial Fibrillation
Nonvalvular atrial fibrillation (AFib) is an irregular heart rhythm not caused by a heart valve problem. In AFib, the heart’s upper chambers beat chaotically, which can lead to blood pooling and clot formation. If these clots detach and travel to the brain, they can cause a stroke. Apixaban is prescribed to lower the risk of stroke and systemic embolism in individuals with nonvalvular AFib.
The recommended dosage for most patients is 5 mg taken twice daily. A reduced dose of 2.5 mg twice daily may be considered for patients who are 80 years or older, weigh 60 kg or less, or have a serum creatinine level of 1.5 mg/dL or higher. Consistently taking apixaban as prescribed is important, as stopping the medication can increase the risk of stroke.
Treatment of Existing Blood Clots
Apixaban treats existing blood clots, specifically deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT is a blood clot in a deep vein, most commonly in the legs. A PE occurs when a DVT travels to the lungs, blocking blood flow.
For initial treatment of DVT and PE, apixaban is prescribed at 10 mg twice daily for the first seven days. The dose is then reduced to 5 mg twice daily for continued therapy. The duration of treatment often ranges from three to six months, though it can be extended based on individual risk factors for recurrence. Apixaban provides a convenient oral treatment option for these conditions, eliminating the need for routine blood monitoring often associated with older anticoagulants.
Prophylaxis of Blood Clots
Apixaban also serves a preventative role, known as prophylaxis, in specific situations. It reduces the risk of recurrent DVT and PE after an individual has completed initial treatment for an existing clot. For continued prevention of recurrent DVT and PE, a dose of 2.5 mg taken twice daily is typically started after at least six months of initial treatment.
Apixaban is also used to prevent DVT following hip or knee replacement surgery. Patients undergoing these procedures face a heightened risk of developing blood clots due to immobility during recovery. For this purpose, the recommended dose is 2.5 mg orally twice daily, with the first dose usually given 12 to 24 hours after surgery. Treatment duration varies, typically 32 to 38 days for hip replacement and 10 to 14 days for knee replacement surgery.
Mechanism of Action
Blood clotting is a complex biological process involving a series of reactions known as the coagulation cascade. This cascade relies on various proteins, referred to as clotting factors, which activate in a specific sequence to form a blood clot. Apixaban works by targeting a specific protein within this process.
Apixaban is classified as a “Factor Xa inhibitor.” Factor Xa is an enzyme central to the coagulation cascade, responsible for converting prothrombin into thrombin. Thrombin then converts fibrinogen into fibrin, which forms the structural meshwork of a blood clot.
By selectively blocking Factor Xa, apixaban interrupts this chain reaction, reducing the generation of thrombin and the subsequent formation of fibrin and blood clots. Unlike some older anticoagulants, apixaban directly inhibits Factor Xa without requiring other cofactors.
Key Safety Information
Like all anticoagulant medications, apixaban carries a main risk of bleeding. This can range from minor bleeding, such as bruising or nosebleeds, to more serious or even life-threatening hemorrhages. Patients should be aware of signs of serious bleeding, which include unusual bruising, prolonged bleeding from cuts, blood in urine or stools, or severe headaches. Any of these signs warrant immediate medical attention.
Apixaban should not be used in individuals with active pathological bleeding. It is also not recommended for patients with severe liver disease or severe renal impairment (creatinine clearance less than 30 mL/min), especially if on dialysis, due to increased bleeding risk. Additionally, patients with prosthetic heart valves or antiphospholipid syndrome are typically not recommended to use apixaban.
It is important to inform healthcare providers about all other medications, supplements, and herbal products being taken. Certain drugs can interact with apixaban, potentially increasing the risk of bleeding or reducing its effectiveness.