Overview of low molecular weight heparins and heparinoids: basic and clinical aspects.

Low molecular weight heparins (LMWHs) are fragments derived by enzymatic or chemical depolymerization of standard heparin (SH). They are approximately one-third the size of SH, with a mean molecular weight of 4,000 to 6,000. LMWHs produce less bleeding for equivalent antithrombotic effects than SH in experimental animals. Clinically LMWHs exhibit different pharmacokinetics than SH; they have much better bioavailability at low doses, a longer …