Antithrombin alfa

Class: Anticoagulants, Miscellaneous
Chemical Name: Antithrombin (human reduced), human antithrombin-III (ATIII)
Molecular Formula: C₂₁₉₁H₃₄₅₁N₅₈₃O₆₅₆S₁₈
CAS Number: 84720-88-7
Brands: ATryn

Medically reviewed by Drugs.com on Jun 9, 2022. Written by ASHP.

Introduction

Biosynthetic (recombinant DNA origin) preparation of human antithrombin III, a naturally occurring anticoagulant.

Uses for Antithrombin alfa

Congenital Antithrombin III Deficiency

Prevention of perioperative and peripartum thromboembolism in patients with congenital antithrombin III deficiency; designated an orphan drug by FDA for use in these conditions.

Short-term thromboprophylaxis with an appropriate anticoagulant recommended in patients with congenital antithrombin III deficiency during high-risk situations (e.g., surgery, pregnancy, postpartum period); antithrombin III concentrates may be used when anticoagulant therapy is neither feasible (e.g., due to a bleeding risk) nor sufficient.

Not indicated for treatment of thromboembolic events.

Heparin Resistance

Has been used for management of heparin resistance during cardiopulmonary bypass (CPB)†.

May reduce requirements for fresh frozen plasma and additional heparin during CPB.

Antithrombin alfa Dosage and Administration

Administration

IV Administration

Administer by IV infusion using 0.22-µm inline filter.

Reconstitution

Allow vials of antithrombin alfa (antithrombin [recombinant]) powder for injection to reach room temperature (20–25°C) ≤3 hours prior to reconstitution.

Reconstitute vial containing approximately 1750 units of drug with 10 mL sterile water for injection immediately before use; do not shake. May be further diluted (e.g., to obtain a concentration of 100 units/mL) for IV administration. Withdraw reconstituted contents of 1 or more vials (depending on calculated dose) into a sterile disposable syringe or add to an infusion bag containing 0.9% sodium chloride injection.

Administer as soon as possible or within 8–12 hours of preparation. May be stored at room temperature until administration. Discard any unused portions.

Rate of Administration

Administer initial IV loading dose over 15 minutes followed by a continuous IV maintenance infusion.

Dosage

Potency expressed in international units (IU, units) as tested against activity of the WHO reference standard. Each vial contains approximately 1750 units.

Use different dosing formulas for treatment of pregnant versus nonpregnant patients. (See Distribution: Special Populations, under Pharmacokinetics and see Elimination: Special Populations, under Pharmacokinetics.)

Adults

Congenital Antithrombin III Deficiency

Pregnant Women

Pregnant women undergoing a surgical procedure should be treated according to the dosing formula for pregnant patients. Initiate treatment prior to delivery or approximately 24 hours before surgery; continue until adequate follow-on anticoagulation is establis.