Low-molecular-weight heparin: Biochemistry, pharmacology, and concurrent drug precautions

The anticoagulant activity and pharmacology of standard heparin (SH) is changed dramatically by the relatively minor molecular modifications that produce low-molecular-weight heparin (LMWH). Consequently, appropriate regional anesthesia management for patients receiving LMWH prophylaxis requires a thorough knowledge of the unique biochemistry and pharmacology of LMWH. In this review, I address the biochemistry and pharmacology of both SH and LMWH. Because oral antiplatelet drugs potentiate the risk of bleeding in patients receiving LMWH prophylaxis, knowledge of the mechanism of action and pharmacology of oral antiplatelet drugs also is reviewed.