Binds to and activates antithrombin III, which as a heparin-ATIII complex inactivates factors IIa (thrombin) and Xa
Variable bioavailability, non-linear pharmacokinetics and unpredictable response.
Effective half-life is 90 minutes subcutaneously, or 30 minutes intravenously.
Reversed with protamine sulfate.
Prevention of venous thromboembolism (DVT / PE)
Treatment of venous thromboembolism (DVT / PE)
ST elevation myocardial infarction (STEMI)
Bridging anticoagulation for initiation / withholding of warfarin
Prevention of thrombosis during haemodialysis
Acute limb ischaemia (unfractionated heparin)
Heparin-induced thrombocytopaenia (HIT) - thrombocytopaenia with arterial and venous thrombosis
Intravenous heparin is monitored using activated partial thromboplastin time (APTT). Alternatively (particularly in the setting of antiphospholipid syndrome), a heparin anti-factor Xa assay can be used.