Apixaban is a medication that belongs to a class of drugs known as oral anticoagulants or blood thinners.

Usage

1. Atrial Fibrillation: Apixaban is used to reduce the risk of stroke and blood clots in individuals with atrial fibrillation, a type of irregular heartbeat that can lead to the formation of blood clots.

2. Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE): It is prescribed to treat and prevent DVT and PE, which are blood clots that can occur in the veins of the legs and travel to the lungs.

3. Post-Orthopedic Surgery: Apixaban may be prescribed after hip or knee replacement surgery to prevent DVT

Dosage

1. Atrial Fibrillation: The standard dosage for reducing the risk of stroke and blood clots in individuals with atrial fibrillation is 5 mg taken orally twice daily.

2. Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE): For the treatment of DVT and PE, the initial recommended dosage is 10 mg taken orally twice daily for the first 7 days, followed by 5 mg taken orally twice daily thereafter.

3. Post-Orthopedic Surgery: After hip or knee replacement surgery, the recommended dosage is 2.5 mg taken orally twice daily for a duration determined by the healthcare provider.

Side Effects

1. Bleeding: Apixaban can increase the risk of bleeding. This may manifest as nosebleeds, bleeding gums, heavier or longer menstrual bleeding, easy bruising, or bleeding that takes longer to stop. Most of these bleeding events are not dangerous and should resolve on their own. However, if the bleeding is severe or persistent, it is important to seek medical attention.

2. Headaches, dizziness, or weakness: These symptoms may occur but are less common.

3. Allergic Reactions: Although rare, some individuals may experience allergic reactions to apixaban. Signs of an allergic reaction may include hives, rash, itching, swelling of the face or tongue, and difficulty breathing. If you experience any of these symptoms, seek immediate medical help.

Precaution

1. Allergies: Inform your doctor and pharmacist if you are allergic to apixaban or any other medications, or if you have any known allergies. It is essential to check the medication guide or consult your pharmacist for a list of the ingredients in apixaban tablets.

2. Artificial Heart Valve: If you have an artificial heart valve, it is important to discuss this with your doctor before taking apixaban. The use of apixaban in individuals with artificial heart valves has not been extensively studied, and alternative anticoagulant options may be considered.

3. Other Medications: Apixaban is processed by certain enzymes in the liver (CYP3A4) and transporters in the gut (P-gp). Medications that interact with these enzymes and transporters can affect the levels of apixaban in the body. It is crucial to inform your doctor about all the medications, supplements, and herbal products you are taking, as they may interact with apixaban. Examples of drugs that may interact with apixaban include ketoconazole, itraconazole, and ritonavir.

4. Feeding Tubes: If you are unable to swallow the tablets, apixaban can be given through certain types of feeding tubes. It is important to follow your doctor's directions carefully if you need to take apixaban through a feeding tube.

5. Continued Use: It is important to continue taking apixaban as prescribed by your doctor, even if you feel well. Stopping apixaban without consulting your doctor may increase the risk of blood clot formation.

Overdose

1. Increased Risk of Bleeding: Taking an excessive amount of apixaban can increase the risk of bleeding. Signs of excessive bleeding that may be serious include passing blood in the urine or stool, severe bruising, nosebleeds that last more than 10 minutes, vomiting or coughing up blood, or sudden severe back pain.

2. Contact Poison Control: If you or someone you know has taken too much apixaban, it is recommended to contact Poison Control immediately. They can provide guidance and assistance. In the United States, you can reach Poison Control at 1-800-222-1222. They are available 24 hours a day and can provide free and confidential help.

3. Limited Information: Reports on patient outcomes after documented apixaban overdose are relatively sparse. However, it is crucial to seek medical attention promptly to assess the situation and receive appropriate care.

Interaction

1. Drug Interactions: Apixaban can interact with various medications, including those that can increase the risk of bleeding. Examples of medications that may interact with apixaban include antiplatelet drugs (such as clopidogrel), nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, and other "blood thinners" like warfarin or enoxaparin. Certain antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), may also interact with apixaban. It is important to inform your healthcare provider about all the medications you are taking to avoid potential interactions.

2. Herbal Supplements: Some herbal supplements can interact with apixaban. St. John's wort, a herbal remedy for depression, can increase the risk of side effects when taken with apixaban. It is important to discuss the use of herbal supplements with your healthcare provider before starting apixaban treatment.

3. P-gp and CYP3A4 Interactions: Apixaban is metabolized by enzymes in the liver, including cytochrome P450 3A4 (CYP3A4), and is a substrate of the P-glycoprotein (P-gp) efflux transporter. Medications that affect these enzymes and transporters can potentially interact with apixaban. Agents that interfere with both P-gp and CYP3A4 are more likely to cause significant interactions with apixaban compared to those that interfere with only one of them.

4. Individual Variations: Interactions can vary depending on individual factors such as age, weight, kidney function, and other specific patient considerations. It is important to inform your healthcare provider about all the medications, supplements, and herbal products you are taking to ensure safe and effective use of apixaban.

Mechanism

Apixaban, sold under the brand name Eliquis, is an anticoagulant medication used to treat and prevent blood clots and to prevent stroke in people with nonvalvular atrial fibrillation. The mechanism of action of apixaban involves directly inhibiting factor Xa, which is an important component in the blood clotting process.

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Factor Xa is a key enzyme involved in the formation of thrombin, which is necessary for blood clot formation. By inhibiting factor Xa, apixaban prevents the formation of thrombin and subsequently reduces the risk of blood clot formation.

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Apixaban is administered orally in tablet form and is rapidly absorbed into the bloodstream. It undergoes metabolism in the liver, primarily through the cytochrome P450 3A4 (CYP3A4) enzyme system. The drug is eliminated through both renal excretion and fecal excretion.

Disclaimer

It is important to talk to a healthcare provider or pharmacist about all medications and supplements being taken, to determine whether any interactions may occur. They can advise on the appropriate use and dosage of aspirin to avoid any potential drug interactions.