[Parenteral anticoagulants. Update on use and monitoring of heparin and its derivatives].

Heparin and its different formulations and derivatives, the first and second generation low molecular weight heparins and pentasaccharides, are indirect parenteral anticoagulants that, with limitations and difficulties, continue to have a privileged place in the modern therapeutic arsenal. Even after many years of use, their unique properties make them the best possible anticoagulant in certain scenarios, such as in pregnancy, end stage renal insufficiency or patients that need a quick and reversible anticoagulation. They are also the anticoagulant of choice when it is important to inhibit clots related to external surfaces where the activation of the intrinsic coagulation pathway is especially relevant. Examples of the importance of these compounds are their nowadays first place recommendation in certain thrombosis like in cancer, hemodialysis, or extracorporeal cardiac devices. Also, in patients with venous thromboembolism and hemodynamic instability, high risk of bleeding or in the acute coronary syndrome, heparins are today the preferred anticoagulant. However, the management of heparins is complex and, in some cases, requires frequent laboratory measurements for monitoring. They can eventually cause severe adverse events, such as life-threatening bleeding episodes or thrombosis associated with immune activation of platelets. Understanding the characteristics of these anticoagulants, their use and correct monitoring will allow us to use the different heparins safely. The role of the haemostasis laboratory is essential to adjust the dose of unfractionated heparin, which have proven to be difficult to manage for the general practitioner. In this document we actualize the laboratory and clinical management of heparins and related drugs in the modern anticoagulation era.