Unfractionated heparin

Unfractionated heparins (which professionals also refer to as standard heparins), are categorised as injectable anticoagulants. They are natural molecules. They are extracted from pig intestine or beef lung when they are intended for human use. They are used to treat and prevent venous and arterial thrombo-embolic events (thromboses, pulmonary embolism, etc.). These are usually "holding" treatments before treatment using oral anticoagulants. Oral anticoagulants are usually vitamin K antagonists.

How do unfractionated heparins work?

The unfractionated heparins are mucopolysaccharides. In other words, they are composed of chains of sugars. The molecules bind to anti-thrombin, a protein produced by the liver which has anticoagulant activity, inhibiting two coagulation factors: thrombin and also factor X.

Do they have any contraindications or precautions?

Like all of the anticoagulants, patients must be monitored because of a risk of bleeding. Specialists also describe a fall in platelet count and allergic reactions. This treatment requires close interval monitoring of the APTT (Activated Partial Thromboplastin Time). This is a test which measures the speed at which bloodcoagulates.

Source: Interview with Dr Yannick Béjot, (Dijon University Hospital), 15 June 2011