Merck Manual

Please confirm that you are a health care professional

honeypot link

Antithrombin Deficiency

By

Joel L. Moake

, MD, Baylor College of Medicine

Last full review/revision Jan 2021| Content last modified Jan 2021
Click here for Patient Education
Topic Resources

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. Homozygous deficiency is probably lethal to the fetus in utero.

Acquired deficiencies occur in patients with disseminated intravascular coagulation, liver disease, or nephrotic syndrome, or during heparin therapy. Heparin exerts its anticoagulant effect by activating antithrombin.

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 of either thrombin (dabigatran) or factor Xa (eg, rivaroxaban, apixaban, edoxaban) can be used in place of warfarin in this disorder.

Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Test your knowledge

Management of Adverse Effects of Cancer Therapy
Nausea and vomiting are common adverse effects of either the cancer itself or of the treatment for cancer. Several drugs are available to administer prior to chemotherapy for anticipatory nausea and vomiting. Of these drugs, which of the following is the most effective yet the most expensive? 
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
 

Also of Interest

 
TOP