Medical application | Heparin

Medical application

Heparin is produced in human and animal organism. In humans, it is synthesized and released by the so-called mast cells. After discovering its great therapeutic value (it was discovered in 1916, first applied to humans in 1935), it was started to be extracted from bovine lungs or pig intestines.

It is one of the most commonly used anticoagulants (coumarins such as Marcumar serve the same purpose, but they act through a different mechanism). Heparin binds to the anticoagulant antithrombin III and enhances its anticoagulant effect. Depending on the length of the chain, it has different effects and in some cases also different properties.

Unfractionated heparin is long-chain and, by binding to antithrombin III, inhibits coagulation factors II and X. During treatment with this heparin, the blood level of the drug must be monitored regularly, as there is a risk of overdose. The consequence would be an increased tendency to bleed (by “liquefying” the blood, so to speak).

Intake: In principle, it is not possible to take the drug as a tablet (peroral), as heparin is not absorbed in the gastrointestinal tract. Therefore it is applied either intravenously (i.e. with an injection into a venous blood vessel) or subcutaneously (i.e. with an injection into the subcutaneous fatty tissue). Unfractionated heparin has the best availability for intravenous application.

Low molecular weight heparin

Low molecular weight heparin is short-chain and, with its binding to antithrombin III, particularly inhibits coagulation factor X. When treated with low-molecular-weight heparin, no close monitoring of the blood level is necessary. Consumation: It is injected subcutaneously.

Side effects

Both heparins carry the risk of an increased bleeding tendency. If heparin is overdosed, its effect can be largely cancelled out (antagonized) by protamine.Protamine is thus the antidote (Greek: antidoto – the given, so to speak the antidote) for heparin.

  • The risk of heparin-induced thrombocytopenia is greater with unfractionated heparin.
  • A distinction is made between type I and type II side effects, whereby the latter can be life-threatening and must lead to an immediate discontinuation of treatment with heparin. There is a sharp drop in the number of blood platelets (thrombocytopenia) in the blood and a clumping of platelets in the blood vessels, which can lead to reduced blood flow. The lethality (mortality) for heparin-induced thrombocytopenia type II is 30%.
  • Osteoporosis (bone fragility) is possible with long-term treatment with heparin
  • Reversible hair loss