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Antithrombin Iii Dosage

Applies to the following strengths: 500 intl units; 1000 intl units

Usual Adult Dose for Antithrombin III Deficiency

Loading dose / target an antithrombin (AT) level of 120% of normal: 120% - baseline AT % x weight (in kg) / 1.4%
-Monitor AT levels at baseline, 20 minutes post-injection (peak), 12 hours post-injection, and pre-injection (trough)

Dose adjustment (as needed) / target AT levels of 80 to 120% of normal: Target % - trough AT % x weight (in kg) / 1.4%
-Monitor AT levels at 20 minutes post-injection (peak), 12 hours post-injection, and pre-injection (trough)

Maintenance dose / target AT levels of 80% to 120% of normal: Loading dose x 0.6 approximately every 24 hours
-Monitor AT levels about every 24 hours, as needed

-Adjust dose and interval based on actual plasma AT levels, clinical condition, and response to therapy.
-Recovery may vary by patient (e.g. AT half-life may be shortened after surgery, hemorrhage, acute thrombosis, or during heparin/low molecular weight heparin use); monitor more frequently.
-When use to control an acute thrombotic episode or prevent thrombosis during/following surgical or obstetrical procedures, raise AT levels to normal for 2 to 8 days, depending on indication, type and extent of surgery, patients medical status and history, and physician judgement.

Use: Treatment and prevention of thromboembolism, including prevention of peri-operative and peri-partum thromboembolism in patients with hereditary antithrombin deficiency.

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available



Safety and efficacy have not been established in patients younger than 18 years.
This drug is not recommended for use in children.

Consult WARNINGS section for additional precautions.


Data not available

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.