Pharmacology · Parenteral direct thrombin inhibitors

Argatroban !

An intravenous anticoagulant that blocks thrombin directly. The usual choice when heparin-induced thrombocytopenia rules out heparin.

Updated 2026-11-01

Class: Parenteral direct thrombin inhibitors
Enzyme: Thrombin (coagulation factor IIa)
ATC code: B01AE03

Thrombin (coagulation factor IIa)Argatroban

The figure shows human thrombin with argatroban in its active site; in this crystal the catalytic serine was changed to alanine (S195A) to study binding.

Target in 3D: Thrombin (coagulation factor IIa). PDB structure 4HFP (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Argatroban is a small synthetic molecule that binds reversibly to the active site of thrombin, both free and clot-bound, without needing antithrombin. It blocks the reactions thrombin drives: fibrin formation, activation of factors V, VIII and XIII, activation of protein C and platelet aggregation.

Argatroban binds the active site of thrombin, reversibly
It needs no antithrombin and reaches clot-bound thrombin
Fibrin formation and thrombin-driven platelet activation stop

Pharmacokinetics

Distribution: Mainly in the extracellular fluid; about half is bound to plasma proteins.
Metabolism: In the liver (hydroxylation and aromatisation); CYP3A4 takes part, but it is not a clinically important route.
Elimination: Mostly in the faeces, through the bile; no adjustment is needed in kidney impairment.
Half-life: Short: about 39 to 51 minutes; coagulation tests return to baseline within 2 to 4 hours after stopping.
Onset and duration: Immediate on starting the infusion.

Indications

Prevention or treatment of thrombosis in heparin-induced thrombocytopenia. Heparin-induced thrombocytopenia →
Anticoagulation during percutaneous coronary intervention in patients with or at risk of HIT. Myocardial Infarction (Heart Attack) →

Adverse effects

Common

Bleeding (gums, puncture sites, gut, urine)
Low blood pressure
Shortness of breath, fever, diarrhoea
Chest pain, back pain, nausea, headache (in PCI)

Contraindications

Major bleeding
Hypersensitivity to argatroban

Key interactions

Heparin: Heparin's effect on the aPTT is allowed to wear off before argatroban starts.
Warfarin: Argatroban raises the PT and INR beyond warfarin alone; the switch follows a defined INR plan.
Antiplatelets, thrombolytics and glycoprotein IIb/IIIa blockers: Add to bleeding risk; combined use with thrombolytics or IIb/IIIa blockers is not established.

What is monitored

aPTT, a few hours after starting and after every change
Liver function, which sets the starting regimen
Haemoglobin, haematocrit and signs of bleeding
INR during the transition to warfarin

Administration and safety

Continuous intravenous infusion with a pump; some products are ready to use and some need dilution, so the label is read before preparing
Weight-based orders are checked by a second person (high-alert medicine)
Reduced starting regimen in liver impairment; avoided in PCI when liver impairment is significant
No specific antidote: excess effect is managed by stopping or slowing the infusion

Nursing care

Baseline aPTT, platelet count, haemoglobin and liver function before starting
Draw the aPTT at the planned times and adjust only by protocol
Watch puncture sites, urine, stools and neurological status for bleeding
During warfarin overlap, interpret the INR knowing argatroban raises it

Pregnancy and breastfeeding

Limited published data have not linked it to fetal harm; untreated thrombosis and bleeding both carry risks in pregnancy.

Test yourself

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

What is the main indication for argatroban?

Prevention or treatment of thrombosis in heparin-induced thrombocytopenia, and anticoagulation during PCI in patients with or at risk of HIT.

Which organ problem changes the argatroban regimen?

Liver impairment, because argatroban is cleared by the liver; kidney impairment needs no adjustment.

Which test is used to follow argatroban?

The aPTT.

Add to my cards (3)

← Back to the class: Parenteral direct thrombin inhibitors

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 - ARGATROBAN injection, solution (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); 4HFP: Structure of thrombin mutant S195a bound to the active site inhibitor argatroban (RCSB Protein Data Bank, 2013).

Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake

Representative model, for educational purposes only.