Antithrombin III (Human)
Action/Kinetics: Antithrombin III (AT-III) is the major plasma inhibitor of thrombin. For therapeutic use it is obtained from plasma of human volunteers. Inactivation of thrombin by AT-III results from formation of a covalent bond causing an inactive 1:1 stoichiometric complex between thrombin and AT-III. AT-III also inactivates other components of the coagulation cascade including factors IXa, Xa, XIa, and XIIa, and plasmin. t 1/2: 2.5 days (based on immunologic assays).
Uses: Hereditary AT-III deficiency in pregnant clients, in clients requiring surgery, and in individuals with thromboembolism.
Special Concerns: Safety and effectiveness have not been determined in children. Even though special precautions are taken to screen plasma donors, clients may develop S&S of viral infections, especially hepatitis C.
Side Effects: GI: Nausea, foul taste in mouth, bowel fullness. CNS: Dizzness, lightheadedness. Respiratory: Chest tightness, shortness of breath, chest pain. Miscellaneous: Chills, cramps, film over eye, hives, fever, oozing, hematoma.
Drug Interactions: The anticoagulant effect of heparin is increased when used concomitantly with AT-III; decrease the dose of heparin during AT-III therapy.
How Supplied: Powder for injection, lyophilized: 500 IU, 1000 IU
If AT-III therapy is indicated for a client with hereditary deficiency to control an acute thrombotic episode or to prevent thrombosis following surgical or obstetrical procedures, increase the AT-III plasma level to normal and maintain for 2-8 days. This will depend on the reason for treatment, type and extensiveness of surgery, medical condition and history of the client, and judgment of the physician.