Apixaban: Complete Guide with FAQs
Introduction
- Apixaban is an anticoagulant (blood thinner) used to reduce the risk of blood clots and stroke.
- It is a direct oral anticoagulant (DOAC) that does not require routine INR monitoring, unlike warfarin.
- Commonly prescribed for conditions like atrial fibrillation, deep vein thrombosis (DVT), and pulmonary embolism (PE).
Class and Mechanism of Action
- Class: Direct Factor Xa Inhibitor (DOAC).
- Mechanism of Action:
- Selectively inhibits factor Xa, a key enzyme in the clotting cascade.
- Prevents the formation of fibrin clots without directly affecting platelet aggregation.
Indications
- Stroke prevention in non-valvular atrial fibrillation (NVAF).
- Treatment and prevention of DVT and PE.
- Prophylaxis of DVT following hip or knee replacement surgery.
- Secondary prevention of recurrent DVT and PE.
Dosage and Administration
For Stroke Prevention in Atrial Fibrillation
- Standard dose: 5 mg twice daily.
- Adjusted dose: 2.5 mg twice daily for patients meeting two of the following criteria:
- Age ≥ 80 years.
- Body weight ≤ 60 kg.
- Serum creatinine ≥ 1.5 mg/dL.
For DVT or PE Treatment
- Initial dose: 10 mg twice daily for 7 days.
- Maintenance dose: 5 mg twice daily.
For DVT Prophylaxis After Surgery
- Hip replacement: 2.5 mg twice daily for 35 days.
- Knee replacement: 2.5 mg twice daily for 12 days.
Administration Tips
- Take at the same time each day, with or without food.
- Do not double doses if a dose is missed; take the next dose at the scheduled time.
Forms and Brand Names
- Forms Available: Tablets (2.5 mg, 5 mg).
- Brand Names and Manufacturers:
- Eliquis (Bristol-Myers Squibb).
- Generic apixaban available in some markets.
Contraindications and Precautions
Contraindications
- Active bleeding.
- Severe hepatic impairment.
- Hypersensitivity to apixaban or its components.
- Patients with mechanical heart valves.
Precautions
- Use cautiously in patients with renal impairment; adjust dose if necessary.
- Increased bleeding risk in patients with a history of gastrointestinal bleeding.
- Avoid abrupt discontinuation without a replacement strategy to prevent thrombotic events.
- Avoid use during pregnancy or breastfeeding unless clearly needed.
Side Effects
Common
- Minor bleeding (e.g., gums, nosebleeds).
- Bruising easily.
Less Common
- Nausea or gastrointestinal discomfort.
- Fatigue.
- Mild dizziness.
Rare but Serious
- Severe bleeding (e.g., intracranial or gastrointestinal hemorrhage).
- Allergic reactions (e.g., rash, swelling, or difficulty breathing).
- Spinal or epidural hematomas in patients undergoing neuraxial anesthesia.
Drug Interactions
- Drugs Increasing Bleeding Risk: Aspirin, NSAIDs, other anticoagulants, antiplatelets.
- Strong CYP3A4 and P-gp Inhibitors (e.g., ketoconazole, ritonavir): May increase apixaban levels, requiring dose adjustment.
- Strong CYP3A4 and P-gp Inducers (e.g., rifampin, carbamazepine): May reduce apixaban levels, reducing efficacy.
- Herbal supplements like St. John’s wort can interfere with effectiveness.
Monitoring Parameters
- No routine INR monitoring is required.
- Monitor for signs of bleeding (e.g., prolonged bleeding, black stools).
- Renal function in patients with kidney impairment or the elderly.
Patient Counseling Points
- Take apixaban exactly as prescribed and do not skip doses.
- Report any unusual bleeding, bruising, or signs of internal bleeding (e.g., dark urine, abdominal pain).
- Avoid activities that increase the risk of injury or bleeding.
- Inform healthcare providers of apixaban use before surgeries or procedures.
- Store tablets at room temperature, away from moisture and heat.
Use in Children
- Not approved for use in pediatric patients.
Use in Pregnancy
- Not recommended unless absolutely necessary due to potential risk to the fetus.
Use in Elderly
- Dose adjustments may be necessary in elderly patients with reduced kidney function or low body weight.
FAQs About Apixaban
Q1: How does apixaban work?
- It inhibits factor Xa, a key enzyme in the clotting process, preventing clot formation.
Q2: Does apixaban require blood tests like warfarin?
- No, routine INR monitoring is not needed.
Q3: Can apixaban be stopped abruptly?
- No, abrupt discontinuation increases the risk of blood clots. Consult your doctor before stopping.
Q4: What should I do if I miss a dose of apixaban?
- Take the missed dose as soon as possible on the same day, then resume your regular schedule.
Q5: Can I drink alcohol while taking apixaban?
- Limit alcohol intake, as it may increase the risk of bleeding.
Q6: How long does apixaban stay in the body?
- Its half-life is about 12 hours, so it stays in the system for approximately 2 days after the last dose.
Q7: Is apixaban safe during pregnancy?
- It is not recommended due to potential risks to the fetus.
Q8: What foods should I avoid while taking apixaban?
- Unlike warfarin, apixaban has no dietary restrictions.
Q9: Can apixaban interact with other medications?
- Yes, certain medications like strong CYP3A4 inhibitors or inducers can affect its levels.
Q10: How does apixaban compare to warfarin?
- Apixaban has fewer drug and dietary interactions and does not require INR monitoring, but warfarin may be preferred for mechanical heart valves.
Q11: Can apixaban be reversed in case of bleeding?
- Yes, andexanet alfa is an FDA-approved reversal agent for apixaban in emergencies.
Q12: Can apixaban cause hair loss?
- Hair loss is not a common side effect of apixaban.
Q13: How long do I need to take apixaban?
- Duration depends on the condition being treated, ranging from a few weeks to lifelong use.
Q14: Is apixaban safe for long-term use?
- Yes, it is often prescribed for long-term management of conditions like atrial fibrillation.
Q15: Can I take apixaban with aspirin?
- Use with caution; it increases the risk of bleeding. Consult your doctor before combining these medications.
