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Apixaban

Apixaban

Eliquis

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Updated: December 06, 2025

Overview

Apixaban is a direct oral anticoagulant (DOAC) that selectively inhibits factor Xa, a key component in the blood coagulation cascade. It is widely used for stroke prevention in non-valvular atrial fibrillation and for the treatment/prevention of venous thromboembolism (VTE). As a newer anticoagulant, apixaban offers several advantages over traditional therapies like warfarin, including predictable pharmacokinetics, fewer food-drug interactions, and no requirement for routine coagulation monitoring. It has demonstrated efficacy in major clinical trials while maintaining a favorable safety profile.

Drug Class

Direct oral anticoagulant (DOAC), Factor Xa inhibitor Therapeutic category: Anticoagulants, Antithrombotics

Mechanism of Action

Apixaban is a highly selective, reversible inhibitor of factor Xa that: • Binds directly to the active site of both free and clot-bound factor Xa • Inhibits conversion of prothrombin to thrombin • Reduces thrombin-mediated platelet activation • Decreases fibrin clot formation This mechanism ultimately prevents thrombus development without affecting existing clots.

Pharmacokinetics

Absorption: Oral bioavailability ~50%, peak plasma concentration in 3-4 hours Distribution: Volume of distribution ~21 L, 87% plasma protein bound Metabolism: Primarily hepatic via CYP3A4/5 with minor contributions from CYP1A2, 2C8, 2C9, 2C19, and 2J2 Excretion: 55% fecal (25% as unchanged drug), 25% renal (mostly as metabolites) Half-life: Approximately 12 hours in healthy subjects

Pharmacodynamics

• Dose-dependent inhibition of factor Xa activity • Prolongs PT/INR and aPTT at therapeutic doses (not used for monitoring) • Anti-factor Xa activity correlates with plasma concentrations • Onset within 3-4 hours after oral administration • No direct effect on platelet aggregation

Indications

• Stroke/systemic embolism prevention in non-valvular atrial fibrillation • Treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE) • Prevention of recurrent DVT/PE • Prophylaxis of venous thromboembolism following hip/knee replacement surgery

Contraindications

Absolute: • Active pathological bleeding • Severe hypersensitivity reactions • Concomitant use with other factor Xa inhibitors Relative: • Recent major surgery • Severe uncontrolled hypertension • Concomitant strong dual CYP3A4/P-gp inhibitors in renal impairment • Conditions with increased bleeding risk

Dosage & Administration

Non-valvular atrial fibrillation: • 5 mg twice daily (2.5 mg twice daily if ≥2 of: age ≥80 years, weight ≤60 kg, or serum creatinine ≥1.5 mg/dL) DVT/PE treatment: • 10 mg twice daily for 7 days, then 5 mg twice daily DVT/PE prevention: • 2.5 mg twice daily after ≥6 months of treatment Post-orthopedic surgery prophylaxis: • 2.5 mg twice daily for 12-35 days (hip) or 12 days (knee)

Special Populations

Pediatric: Not approved for use in children Geriatric: Increased bleeding risk in elderly (especially >75 years) Renal impairment: Not recommended in severe impairment (CrCl <15 mL/min) Hepatic impairment: Avoid in severe hepatic impairment (Child-Pugh C)

Adverse Effects

Common (>10%): • Minor bleeding (epistaxis, gingival bleeding) • Bruising • Nausea Serious (<1%): • Major bleeding (GI, intracranial) • Spinal/epidural hematoma • Anaphylaxis

Drug Interactions

• Strong CYP3A4/P-gp inhibitors (ketoconazole, ritonavir): Increase apixaban levels • Strong CYP3A4/P-gp inducers (rifampin, carbamazepine): Decrease apixaban levels • Other anticoagulants/antiplatelets: Increase bleeding risk • NSAIDs: May increase gastrointestinal bleeding risk

Warnings & Precautions

• Black Box Warning: Premature discontinuation increases thrombotic risk • Increased bleeding risk with renal impairment • Spinal/epidural hematoma risk with neuraxial anesthesia • No routine coagulation monitoring required • Consider bleeding risk in elderly patients

Pregnancy & Lactation

Pregnancy: Category B • Use only if potential benefit justifies risk • Limited human data Lactation: Unknown if excreted in milk • Not recommended during breastfeeding

Monitoring Parameters

• Signs/symptoms of bleeding • Renal function (at least annually) • Hemoglobin/hematocrit if bleeding suspected • Liver function tests periodically • No routine coagulation monitoring required

Patient Counseling

• Take exactly as prescribed without missing doses • Report any unusual bleeding or bruising • Avoid activities with high injury risk • Inform all healthcare providers about apixaban use • Do not stop without medical advice • Avoid OTC NSAIDs unless approved by provider

Storage & Stability

Store at 20-25°C (68-77°F) • Keep in original container • Protect from moisture • Discard unused medication after expiration date

Clinical Pearls

• No specific reversal agent required for minor bleeding • Consider prothrombin complex concentrate (PCC) for major bleeding • Half-dose regimen for AF patients with multiple risk factors • Can be taken with or without food • Consider transition protocol when switching from other anticoagulants

References

• Eliquis® (apixaban) Prescribing Information • Connolly SJ, et al. ARISTOTLE trial. N Engl J Med. 2011 • Agnelli G, et al. AMPLIFY trial. N Engl J Med. 2013 • ACC/AHA/HRS Atrial Fibrillation Guidelines 2019