Prescribing-label excerpts
Heparin Sodium
Reference for: Heparin. Source presentation: injection, solution. Source route: intravenous; subcutaneous.
Mechanism of action
Heparin interacts with the naturally occurring plasma protein, antithrombin III, to induce a conformational change, which markedly enhances the serine protease activity of antithrombin III, thereby inhibiting the activated coagulation factors involved in the clotting sequence, particularly Xa and IIa. Small amounts of heparin inhibit Factor Xa, and larger amounts inhibit thrombin (Factor IIa). Heparin also prevents the formation of a stable fibrin clot by inhibiting the activation of the fibrin stabilizing factor. Heparin does not have fibrinolytic activity; therefore, it will not lyse existing clots.
Pharmacokinetics
Absorption — Heparin is not absorbed through the gastrointestinal tract and therefore administered via parenteral route. Peak plasma concentration and the onset of action are achieved immediately after intravenous administration.
Distribution — Heparin is highly bound to antithrombin, fibrinogens, globulins, serum proteases and lipoproteins. The volume of distribution is 0.07 L/kg.
Selected passages from the cited U.S. prescribing label. The studies concern the source product and populations named in each passage; they do not establish Walter-product bioequivalence, an approved indication, or the kinetics of another fixed combination. Tables and the full prescribing information remain available in the source.
Source: DailyMed: Heparin Sodium — injection, solution
Reference accessed . Label revision: 2026-08-25.
