Low-molecular-weight heparins (LMWHs)

Low-molecular-weight heparins (LMWHs) provide rapid and effective anticoagulation, playing a crucial role in both the prevention and treatment of venous thromboembolism (VTE) and other thrombotic conditions. LMWHs have largely replaced unfractionated heparin (UFH) in many clinical applications due to their improved safety profile, including a lower risk of heparin-induced thrombocytopenia (HIT), and their ease of use.

Pharmacology and Clinical Use

LMWHs, such as enoxaparin, dalteparin, and tinzaparin, are derived from UFH through a process of depolymerization, resulting in shorter polysaccharide chains. This mechanism reduces the formation of fibrin clots and provides effective anticoagulation.

LMWHs possess a smaller molecular size compared to UFH, with an average molecular weight typically between 4,000 and 6,500 Da. This smaller size enhances their bioavailability and allows for more predictable pharmacokinetics, including a longer half-life and a more consistent anticoagulant effect Chen et al. (2019). LMWHs primarily exert their anticoagulant effect by binding to antithrombin III, which subsequently inhibits factor Xa and to a lesser extent thrombin (factor IIa) (Litov et al., 2021). This mechanism reduces the formation of fibrin clots and provides effective anticoagulation.

Key pharmacological advantages of LMWHs include:

• Higher anti-Xa to anti-IIa activity compared to UFH, providing more targeted inhibition of...