Makindo Medical Notes.com

There are two main types - unfractionated (UFH) and low molecular weight Heparin (LMWH)

About: Always check the BNF or equivalent for prescribing advice

• Used both in treatment and prevention of thrombosis
• A collection of polysaccharides derived from porcine gastric mucosa

Types

• Unfractionated: composed of a mixture of naturally occurring glycosaminoglycans with polysaccharide chains. The molecular weight varies from 5,000-30,000. It is normally given IV and can be reversed by stopping the infusion and giving protamine.
• Low Molecular weight Heparin is made from unfractionated: composed of a mixture of naturally occurring glycosaminoglycans with polysaccharide chains. The molecular weight varies from 4,000-6,500. It is much more difficult to reverse with a longer half-life.

Cautions

• Thrombocytopenia, haemophilias, liver failure, renal failure
• Systolic >200 mm Hg or diastolic >120 mm Hg
• Active peptic ulcer, oesophageal varices
• Aneurysm, proliferative retinopathy, recent organ biopsy
• Recent trauma or surgery to head, orbit, spine, recent stroke
• Confirmed intracranial or intraspinal bleed
• History of Heparin-induced thrombocytopenia or thrombosis

Action

• All Heparins work by binding to Antithrombin III which deactivates thrombin and so clotting. Mainly anti-Xa activity
• Low molecular weight Heparins also enhance anti-IIa activity

Management of side effects

• Bleeding - give protamine, transfuse
• Heparin induced thrombocytopenia: Seen in 5% which is more common the longer treatment duration. Stop all Heparins and seek haematology advice.
• Hyperkalaemia
• Osteoporosis with long term use.
• With significant concern about bleeding speak to haematology.