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Heparin
- Rapid onset, short duration of action
- impairs the blood coagulation cascade
Route
- IV
- S/C
- monitor Activated
partial thromboplastin time
- 4-6hrs after starting treatment
- every 6hr until two consecutive readings are within the target range
- thereafter at least twice daily
Indications
- To prevent thrombus formation (e.g. thromboprophylaxis during surgery)
- To prevent thrombus extension (e.g. treatment of DVT)
- To prevent thrombosis in extracorporeal circulation (e.g. haemodialysis,
haemoperfusion, membrane oxygenators, artificial organs) and intravenous
cannulae
- To maintain patency of the vessel following thrombolysis with rTPA
(recombinant human tissue plasminogen activator)
- Arterial embolism
- Disseminated intravascular coagulation (DIC) when DIC is associated with
clinical thrombosis – requires specialist input and meticulous laboratory
control
Contraindications
- Haemophilia and other haemorrhagic disorders
- thrombocytopenia (including history of Heparin-Induced
Thrombocytopenia)
- peptic ulcer,
- recent cerebral haemorrhage,
- severe hypertension,
- severe liver disease (including oesophageal varices),
- after major trauma or recent surgery (especially to eye or nervous
system),
- hypersensitivity to heparin
Mechanism of action
- binds to and activates circulating antithrombin III (AT III)
- activated AT III forms a complex with thrombin (factor IIa)
- prevents thrombin from converting soluble fibrinogen to insoluble fibrin
(factor Ia)
- prevents further thrombus formation
Side Effects
Reversed by
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