Pharmacology · Direct oral anticoagulants (DOACs)

Apixaban !

An oral anticoagulant that blocks clotting factor Xa directly. Used in atrial fibrillation and venous thrombosis, with no routine INR checks.

Updated 2026-11-01

Class: Direct oral anticoagulants (DOACs)
Enzyme: Coagulation factor Xa
ATC code: B01AF02

Coagulation factor XaApixaban

The figure shows human factor Xa with apixaban in its active site.

Target in 3D: Coagulation factor Xa. PDB structure 2P16 (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Apixaban binds the active site of factor Xa and blocks it, without needing antithrombin. It inhibits free factor Xa, factor Xa bound to clots and the prothrombinase complex, so less thrombin is made and less fibrin forms. It has no direct effect on platelets, but by lowering thrombin it reduces thrombin-driven platelet aggregation.

Apixaban binds the active site of factor Xa
Free and clot-bound Xa and prothrombinase are blocked
Less thrombin is made, so less fibrin forms

Pharmacokinetics

Absorption: By mouth, about half of the dose is absorbed; food does not change it. Peak levels come 3 to 4 hours after a dose.
Distribution: About 87% bound to plasma proteins.
Metabolism: In the liver, mainly by CYP3A4; it is also carried by P-glycoprotein.
Elimination: Through urine and faeces; the kidneys handle about a quarter of its clearance.
Half-life: About 12 hours; the effect lasts at least 24 hours after the last dose.

Indications

Prevention of stroke and systemic embolism in nonvalvular atrial fibrillation. Atrial fibrillation →
Treatment of deep vein thrombosis and prevention of recurrence; prevention after hip or knee replacement. Deep vein thrombosis →
Treatment of pulmonary embolism and prevention of recurrence. Pulmonary embolism →

Adverse effects

Common

Bleeding: bruising, nosebleeds, gum bleeding
Blood in the urine
Nausea

Contraindications

Active pathological bleeding
Severe hypersensitivity to apixaban
Not recommended: prosthetic heart valves, triple-positive antiphospholipid syndrome, severe liver impairment, pregnancy

Key interactions

Combined strong CYP3A4 and P-glycoprotein inhibitors (ketoconazole, itraconazole, ritonavir): Raise apixaban levels and the risk of bleeding.
Combined strong CYP3A4 and P-glycoprotein inducers (rifampicin, carbamazepine, phenytoin, St John's wort): Lower apixaban levels; to be avoided because protection against clots falls.
Aspirin, other antiplatelets, NSAIDs, other anticoagulants, SSRIs and SNRIs: Add to the risk of bleeding.

What is monitored

Signs of bleeding and haemoglobin when needed
Kidney and liver function before starting and over time
Neurological checks after spinal or epidural procedures

Administration and safety

Oral; for people who cannot swallow, the tablet may be crushed and given in water or through a nasogastric tube, as the label describes
Missed doses and early stopping raise the risk of stroke; changes are planned with the treating team
Timing around surgery, epidural catheters and spinal puncture follows a written plan
Its anti-Xa effect can be reversed with andexanet alfa; dialysis removes little of it

Nursing care

Ask about bleeding history, kidney and liver disease and other drugs that affect clotting before the first dose
Watch for bleeding: black stools, blood in urine, unusual bruising, severe headache
After neuraxial anaesthesia, check legs for numbness or weakness, and back pain
Teach the patient not to stop it on their own and to tell every dentist and surgeon

Pregnancy and breastfeeding

Data in pregnancy are limited and it is not recommended; it can increase bleeding at delivery, especially with neuraxial anaesthesia.

Test yourself

Think of the answer, then tap the question to see it.

Which enzyme does apixaban block, and does it need antithrombin?

Factor Xa, directly: it binds the active site of free and clot-bound Xa without antithrombin.

Which drug interaction raises apixaban levels the most?

Drugs that strongly inhibit both CYP3A4 and P-glycoprotein, such as ketoconazole, itraconazole or ritonavir.

In which patients is apixaban not recommended even though they need an anticoagulant?

People with prosthetic heart valves and people with triple-positive antiphospholipid syndrome; warfarin is used there.

Which agent reverses apixaban's anti-Xa effect?

Andexanet alfa, a modified factor Xa that binds it; protamine and vitamin K do not work.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: DailyMed - APIXABAN tablet, film coated (DailyMed (U.S. National Library of Medicine), 2026); Apixaban: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2025); eEML - Electronic Essential Medicines List (World Health Organization, 2025); 2P16: Factor Xa in Complex with the Inhibitor APIXABAN (BMS-562247) (RCSB Protein Data Bank, 2007).

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Representative model, for educational purposes only.