Drug Information: Apixaban
Apixaban is an anticoagulant medication commonly used to prevent and treat blood clots. It is a direct factor Xa inhibitor, meaning it directly blocks the activity of factor Xa, a key protein in the coagulation cascade. By inhibiting factor Xa, apixaban prevents the formation of thrombin and ultimately the formation of blood clots. Apixaban is frequently prescribed for conditions such as atrial fibrillation, deep vein thrombosis (DVT), and pulmonary embolism (PE).
Category
Anticoagulant
Mechanism of Action
Apixaban is a direct factor Xa inhibitor. Factor Xa is a crucial serine protease in the coagulation cascade, the series of events that lead to blood clot formation. Specifically, factor Xa converts prothrombin to thrombin. Thrombin then converts fibrinogen to fibrin, which is the structural protein of a blood clot. Apixaban selectively and reversibly blocks the active site of factor Xa, both free factor Xa and factor Xa bound in the prothrombinase complex. This inhibition prevents the conversion of prothrombin to thrombin, thereby reducing thrombin generation and the subsequent formation of fibrin clots. Unlike older anticoagulants like warfarin, apixaban has a more predictable anticoagulant effect and does not require routine monitoring of blood clotting parameters. Its direct action on factor Xa makes it a more targeted and efficient anticoagulant.
Clinical Uses
Apixaban is primarily used to reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation. Atrial fibrillation, a common heart rhythm disorder, increases the risk of blood clots forming in the heart, which can then travel to the brain and cause a stroke. Apixaban is also used for the treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE), as well as for the prevention of recurrent DVT and PE. Furthermore, it’s used for the prophylaxis of DVT that may lead to PE in patients undergoing hip or knee replacement surgery. The efficacy and safety of apixaban have been demonstrated in numerous clinical trials, making it a cornerstone of anticoagulation therapy.
Dosage
Adult Dosage:
* Atrial Fibrillation: The typical dose is 5 mg twice daily. However, a lower dose of 2.5 mg twice daily may be considered in patients with at least two of the following characteristics: age ≥80 years, body weight ≤60 kg, or serum creatinine ≥1.5 mg/dL.
* DVT/PE Treatment: 10 mg twice daily for the first 7 days, followed by 5 mg twice daily.
* DVT/PE Prevention (after hip or knee replacement): 2.5 mg twice daily, started 12 to 24 hours after surgery. The duration of treatment varies depending on the type of surgery.
Pediatric Dosage:
The safety and effectiveness of apixaban in pediatric patients have not been established.
Route of Administration: Oral. Apixaban tablets should be swallowed whole with water. They can be crushed and mixed with water or apple juice if the patient has difficulty swallowing, and administered orally or via nasogastric tube.
Indications
* Prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation.
* Treatment of deep vein thrombosis (DVT).
* Treatment of pulmonary embolism (PE).
* Prevention of recurrent DVT and PE.
* Prophylaxis of DVT following hip or knee replacement surgery.
Contraindications
* Active major bleeding.
* Known hypersensitivity to apixaban or any of its components.
* Severe hepatic impairment associated with coagulopathy and clinically relevant bleeding risk.
* Use with other anticoagulants, except under specific circumstances such as transitioning to or from other anticoagulant therapies or when unfractionated heparin is given at doses necessary to maintain an open central venous or arterial catheter.
* Patients with prosthetic heart valves (increased risk of thromboembolic events).
FAQ
Q: What is apixaban used for?
A: Apixaban is used to prevent blood clots in conditions like atrial fibrillation and to treat and prevent deep vein thrombosis (DVT) and pulmonary embolism (PE).
Q: How does apixaban work?
A: Apixaban works by directly inhibiting factor Xa, a key protein in the coagulation cascade, thereby preventing blood clot formation.
Q: What are the common side effects of apixaban?
A: The most common side effect is bleeding. Other side effects can include nausea and anemia.
Q: What should I do if I miss a dose of apixaban?
A: Take the missed dose as soon as you remember, unless it is almost time for your next dose. In that case, skip the missed dose and continue with your regular dosing schedule. Do not double the dose to catch up.
Q: Can I take apixaban with other medications?
A: Apixaban can interact with other medications, so it’s important to tell your doctor about all the medications you are taking, including over-the-counter drugs and supplements. Some medications may increase the risk of bleeding when taken with apixaban.
Q: What should I do before surgery or a dental procedure if I am taking apixaban?
A: Inform your doctor or dentist that you are taking apixaban. You may need to stop taking apixaban temporarily before the procedure to reduce the risk of bleeding. Follow your doctor’s instructions carefully.
Q: Is there an antidote for apixaban?
A: Yes, andexanet alfa is an antidote that can reverse the effects of apixaban in cases of life-threatening or uncontrolled bleeding.
Q: How often will I need blood tests while taking apixaban?
A: Unlike warfarin, apixaban typically does not require routine monitoring of blood clotting parameters. However, your doctor may order blood tests to monitor your kidney function or to check for anemia if you experience any symptoms.
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