Low molecular weight heparins in special populations.

Low molecular weight heparins (LMWH) are replacing unfractionated heparin (UH) as safe and effective agents for the prevention and treatment of thromboembolism. Although LMWH offer many advantages over UH, usage is less clearly defined in certain special populations, including renal dysfunction, obesity and pregnancy. This article will briefly review the pharmacology of LMWH and discuss usage in these special populations.