Heparin - Natural Degradation or Clearance

Natural Degradation or Clearance

Unfractionated heparin has a half-life of approximately one to two hours after infusion, whereas low-molecular-weight heparin has a half-life that is about four times longer. Lower doses of heparin have a much shorter half-life than larger doses of heparin. Heparin binding to macrophage cells is internalized and depolymerized by the macrophages. Heparin also rapidly binds to endothelial cells, which precludes the binding to antithrombin that results in anticoagulant action. For higher doses of heparin, endothelial cell binding will be saturated, such that clearance of heparin from the bloodstream by the kidneys will be a slower process.