Merck Manual

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Antithrombin Deficiency

By

Joel L. Moake

, MD, Baylor College of Medicine

Medically Reviewed Jan 2021 | Modified Sep 2022
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Because antithrombin inhibits thrombin and factors Xa, IXa, and XIa, deficiency of antithrombin predisposes to venous thrombosis.

Antithrombin is a plasma protein that inhibits thrombin and factors Xa, IXa, and XIa, thereby inhibiting thrombosis.

Heterozygous deficiency of antithrombin has a prevalence of about 0.2 to 0.4%; about half of people affected develop venous thromboses Deep Venous Thrombosis (DVT) Deep venous thrombosis (DVT) is clotting of blood in a deep vein of an extremity (usually calf or thigh) or the pelvis. DVT is the primary cause of pulmonary embolism. DVT results from conditions... read more Deep Venous Thrombosis (DVT) . Homozygous deficiency is probably lethal to the fetus in utero.

Laboratory testing is done for patients with an unexplained blood clot and involves quantification of the capacity of patient plasma to inhibit thrombin in the presence of heparin.

Treatment of Antithrombin Deficiency

  • Warfarin

Oral warfarin is used for prophylaxis against venous thromboembolism.

It is probable, but not yet certain, that the direct oral anticoagulant (DOAC) inhibitors Treatment In healthy people, homeostatic balance exists between procoagulant (clotting) forces and anticoagulant and fibrinolytic forces. Numerous genetic, acquired, and environmental factors can tip... read more of either thrombin (dabigatran) or factor Xa (eg, rivaroxaban, apixaban, edoxaban) can be used in place of warfarin in this disorder.

Drugs Mentioned In This Article

Drug Name Select Trade
Recothrom, Thrombi-Gel , Thrombin-JMI, Thrombin-JMI Epistaxis, Thrombi-Pad, Thrombogen
Hepflush-10 , Hep-Lock, Hep-Lock U/P, Monoject Prefill Advanced Heparin Lock Flush, SASH Normal Saline and Heparin
Coumadin, Jantoven
Pradaxa
ANDEXXA
Xarelto, Xarelto Granules, Xarelto Starter Pack
Eliquis
Savaysa
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NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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